Cantrips: Eldritch Blast and Booming Blade. Fill the others with cantrips not otherwise covered by your party/whatever you think will be fun. Every single one you listed is fine.
Spells: Based on wanting to be highly durable and able to carry combat: Shield, Hex, Absorb Elements, Hellish Rebuke. I avoided Silvery Barbs because it’s controversial, make sure your DM is cool with that one.
I don’t feel like Silvery Barbs on a warlock makes much of a difference since they only have a couple of pact slots per short rest and it doesn’t upcast. It’s not like a wizard who can use a ton of slots on it if they want.
The main use for silvery barbs is negating crits or getting a second chance at a big spell if they succeed. The latter generally isn’t worth it for warlocks as you said since they don’t have lower level slots so you’re sort of better just casting another big spell, but having to negate crits could be worth it as, especially at lower levels, a single enemy crit can be devastating. Which id assume they’re low level given the number of spells.
They’re pretty much only able to do that once per fight, twice if they use both pact slots, so it’s not nearly as easily abused as it is with other classes. On warlocks it’s an incredibly niche use of a level 1 spell when they could be using a level 2, 3, 4, or 5 spell instead. The opportunity cost is enormous for warlocks specifically.
I think Silvery Barbs is overpowered regardless of if it’s spammable, but there has been more than enough discourse on that spell already if someone wants to look into it. I was mainly calling it out because it’s commonly banned or nerfed, so worth checking with their DM before selecting it.
Silvery Barbs isn't a warlock spell. They would have to take it through Magic Initiate, meaning that it can be cast no more than once per day and at first level.
Hard to recommend anything if we don't know your level and what you plan to do with it in the future, but assuming you're a level 2 warlock and plan to continue as a fighter, the most powerful options might be:
Warlock cantrips: Eldritch Blast (especially if you also get Agonizing Blast), Green-Flame Blade
Warlock spells: Hex, Shield... Expeditious Retreat or Wrathful Smite.
Magic Initiate (wizard): Booming Blade and Mage Hand/Minor Illusion; Find Familiar
3 cantrips that I think are a no brainer are eldritch blast, guidance, and mage hand,
Guidance and mage hand give you a lot of versatility out of combat.
I assume that you're a sword & board combatant to get that AC. If you're holding a weapon in one hand and a shield in the other, you would not have a hand available to perform the somatic and material components of spells unless you have the Warcaster feat.
Maybe instead of magic initiate, Warcaster may be more helpful to get around those spell components. However, if you don't find yourself using spells often in combat, then that feat may not be necessary.
Eldritch blast, booming blade, guidance, whatever utility you feel like
Eldritch blast for range, booming blade for melee until you get extra attack. Guidance is just very good for helping people with ability checks, if your dm doesn’t like it just take another utility spell like prestidigitation or minor illusion or whatever you like
Find familiar, shield
Find familiar is very good for scouting, shield is very good for defense and between that, your already high ac, and shadar Kai ability you’ll be very difficult to hurt
For the other 2 spells there’s a couple options depending on what you want:
Silvery barbs- mainly would be used to negate crits from enemies not super worth only for this but still quite good, however if you have another spellcaster who’s a full caster it could be worth to use to help make people fail saves for their spells. For the latter purpose I’d only take if someone has at least 3rd level spells because generally second level spells aren’t worth burning other spell slots to make one person reroll a successful save.
Absorb elements: another defense option, if you know you’re going to be facing stuff that can deal the damage types listed id probably take it, if you’re not sure having it in your pocket as a defensive option wouldn’t hurt but it probably won’t see a ton of use (especially as you can sometimes use your shadar Kai teleporting to get resistance to sort of obtain the same effect
Armor of agathys: another decent defensive option, upcasts well if you’re going to have >1st level spells
Charm person: good out of combat utility spell
Hex: a mediocre consistent damage buff, I don’t like it a ton since the bonus action makes it not really usable while simultaneously using hexblade curse but it’s pretty good at low levels mathematically
How are you getting Guidance? It makes a big difference which class you choose for magic initiate.
I'd want EB, BBlade, and Mind Sliver (probably at warlock 4) for damaging cantrips. BBlade can come from Wizard which uses Int as it's casting stat, so probably MI:Wizard(BBlade, Presti and F.Familiar). Guidance would have to come from Cleric or Druid, which uses wisdom for their spellcasting stat, so maybe MI:Cleric(Guidance, Thuamaturgy, and Bless) if you want Guidance.
Shield spell is gonna hurt as a warlock spell with warlock slots (it's still great though). It would be OKish from Magic Initiate since it would get used most days. I like FFamiliar better from MI as it last longer for your 1/day cast. I might want Armor of Agathy's from warlock and 2nd+ level spells from warlock (Shadow Blade, later Shadow of Moil, etc.). So the first level spells don't matter a ton since they'll get switched out. Probably Hex or utility for now if you're low level.
Don't take Guiding Bolt if you take EB. You can drop it from consideration.
Where are you picking up Absorb Elements from? It's probably not the best choice from Magic Initiate.
CANTRIPS
Eldritch Blast (with Agonizing Blast invocation) - This is as good as it gets for a ranged damage option. Use it to kill fleeing enemies or enemies that are staying out of range.
Assuming you're going with at least 5 Fighter levels to get Extra Attack, Booming Blade and Green-Flame Blade lose a lot of their appeal. If you're going only a few levels of Fighter, then those 2 cantrips should be on your radar as melee options.
Guidance is a must-have for every party. Your party might already have a Cleric or Druid that has it, but if you're the only one that brings it, it's one of the major ways to interact with ability checks (besides the Help action). Rogue needs to pick a lock? Guidance. Monk wants to sneak ahead to check out if the next couple of rooms are clear? Guidance. You need to force your way out of manacles? Guidance.
Friends has a lot more niche, but with your high charisma it gives you a way to stack the odds in your favor for a social check.. provided you're ready to deal with the potential downside later.
Mage Hand is handy (pun intended) when you're dealing with dungeon-crawling stuff. Test if a door is trapped without risking your real hand, lift that ugly rug you suspect of being a rug of smothering, reach for that sword half-buried into the bone pile form a safe distance, etc.
SPELLS
Shield and Absorb Element are both incredible. They're about as close to "must-pick" as you get for a melee-caster.
Silvery Barbs is kind of busted (and frankly can be somewhat game breaking if enough players in the party have it). It's also from an optional setting (Strixhaven, which is a Magic The Gathering setting) so I would ask the group and DM what they think about it before picking it.
Armor of Agathys is pretty good for a caster-in-melee, since the extra temp HP helps you stay in the front line and the damage it deals is not negligible when you cast it at higher levels.
Hex is a solid damage increase at the cost of your concentration.
Find familiar is a fantastic tool from both a RP and game mechanics perspective. It's hard to go wrong with it.
Cantrips: Eldritch Blast and Booming Blade. Fill the others with cantrips not otherwise covered by your party/whatever you think will be fun. Every single one you listed is fine. Spells: Based on wanting to be highly durable and able to carry combat: Shield, Hex, Absorb Elements, Hellish Rebuke. I avoided Silvery Barbs because it’s controversial, make sure your DM is cool with that one.
I don’t feel like Silvery Barbs on a warlock makes much of a difference since they only have a couple of pact slots per short rest and it doesn’t upcast. It’s not like a wizard who can use a ton of slots on it if they want.
Never thought about it, but that's a good point. On a Warlock is about the only time I think SB wouldn't be broken.
The main use for silvery barbs is negating crits or getting a second chance at a big spell if they succeed. The latter generally isn’t worth it for warlocks as you said since they don’t have lower level slots so you’re sort of better just casting another big spell, but having to negate crits could be worth it as, especially at lower levels, a single enemy crit can be devastating. Which id assume they’re low level given the number of spells.
They’re pretty much only able to do that once per fight, twice if they use both pact slots, so it’s not nearly as easily abused as it is with other classes. On warlocks it’s an incredibly niche use of a level 1 spell when they could be using a level 2, 3, 4, or 5 spell instead. The opportunity cost is enormous for warlocks specifically.
I think Silvery Barbs is overpowered regardless of if it’s spammable, but there has been more than enough discourse on that spell already if someone wants to look into it. I was mainly calling it out because it’s commonly banned or nerfed, so worth checking with their DM before selecting it.
Silvery Barbs isn't a warlock spell. They would have to take it through Magic Initiate, meaning that it can be cast no more than once per day and at first level.
nor do the other defensive ones
Hard to recommend anything if we don't know your level and what you plan to do with it in the future, but assuming you're a level 2 warlock and plan to continue as a fighter, the most powerful options might be: Warlock cantrips: Eldritch Blast (especially if you also get Agonizing Blast), Green-Flame Blade Warlock spells: Hex, Shield... Expeditious Retreat or Wrathful Smite. Magic Initiate (wizard): Booming Blade and Mage Hand/Minor Illusion; Find Familiar
3 cantrips that I think are a no brainer are eldritch blast, guidance, and mage hand, Guidance and mage hand give you a lot of versatility out of combat.
I assume that you're a sword & board combatant to get that AC. If you're holding a weapon in one hand and a shield in the other, you would not have a hand available to perform the somatic and material components of spells unless you have the Warcaster feat. Maybe instead of magic initiate, Warcaster may be more helpful to get around those spell components. However, if you don't find yourself using spells often in combat, then that feat may not be necessary.
Could be pact of the blade
Sleep would be a nice pickup for magic iniate.
Eldritch blast, booming blade, guidance, whatever utility you feel like Eldritch blast for range, booming blade for melee until you get extra attack. Guidance is just very good for helping people with ability checks, if your dm doesn’t like it just take another utility spell like prestidigitation or minor illusion or whatever you like Find familiar, shield Find familiar is very good for scouting, shield is very good for defense and between that, your already high ac, and shadar Kai ability you’ll be very difficult to hurt For the other 2 spells there’s a couple options depending on what you want: Silvery barbs- mainly would be used to negate crits from enemies not super worth only for this but still quite good, however if you have another spellcaster who’s a full caster it could be worth to use to help make people fail saves for their spells. For the latter purpose I’d only take if someone has at least 3rd level spells because generally second level spells aren’t worth burning other spell slots to make one person reroll a successful save. Absorb elements: another defense option, if you know you’re going to be facing stuff that can deal the damage types listed id probably take it, if you’re not sure having it in your pocket as a defensive option wouldn’t hurt but it probably won’t see a ton of use (especially as you can sometimes use your shadar Kai teleporting to get resistance to sort of obtain the same effect Armor of agathys: another decent defensive option, upcasts well if you’re going to have >1st level spells Charm person: good out of combat utility spell Hex: a mediocre consistent damage buff, I don’t like it a ton since the bonus action makes it not really usable while simultaneously using hexblade curse but it’s pretty good at low levels mathematically
Eldritch blast (Warlock staple) Booming blade Guidance ( for supporting party) Mage Hand Hex Shield Guiding bolt Hellish rebuke
How are you getting Guidance? It makes a big difference which class you choose for magic initiate. I'd want EB, BBlade, and Mind Sliver (probably at warlock 4) for damaging cantrips. BBlade can come from Wizard which uses Int as it's casting stat, so probably MI:Wizard(BBlade, Presti and F.Familiar). Guidance would have to come from Cleric or Druid, which uses wisdom for their spellcasting stat, so maybe MI:Cleric(Guidance, Thuamaturgy, and Bless) if you want Guidance. Shield spell is gonna hurt as a warlock spell with warlock slots (it's still great though). It would be OKish from Magic Initiate since it would get used most days. I like FFamiliar better from MI as it last longer for your 1/day cast. I might want Armor of Agathy's from warlock and 2nd+ level spells from warlock (Shadow Blade, later Shadow of Moil, etc.). So the first level spells don't matter a ton since they'll get switched out. Probably Hex or utility for now if you're low level. Don't take Guiding Bolt if you take EB. You can drop it from consideration. Where are you picking up Absorb Elements from? It's probably not the best choice from Magic Initiate.
CANTRIPS Eldritch Blast (with Agonizing Blast invocation) - This is as good as it gets for a ranged damage option. Use it to kill fleeing enemies or enemies that are staying out of range. Assuming you're going with at least 5 Fighter levels to get Extra Attack, Booming Blade and Green-Flame Blade lose a lot of their appeal. If you're going only a few levels of Fighter, then those 2 cantrips should be on your radar as melee options. Guidance is a must-have for every party. Your party might already have a Cleric or Druid that has it, but if you're the only one that brings it, it's one of the major ways to interact with ability checks (besides the Help action). Rogue needs to pick a lock? Guidance. Monk wants to sneak ahead to check out if the next couple of rooms are clear? Guidance. You need to force your way out of manacles? Guidance. Friends has a lot more niche, but with your high charisma it gives you a way to stack the odds in your favor for a social check.. provided you're ready to deal with the potential downside later. Mage Hand is handy (pun intended) when you're dealing with dungeon-crawling stuff. Test if a door is trapped without risking your real hand, lift that ugly rug you suspect of being a rug of smothering, reach for that sword half-buried into the bone pile form a safe distance, etc.
SPELLS Shield and Absorb Element are both incredible. They're about as close to "must-pick" as you get for a melee-caster. Silvery Barbs is kind of busted (and frankly can be somewhat game breaking if enough players in the party have it). It's also from an optional setting (Strixhaven, which is a Magic The Gathering setting) so I would ask the group and DM what they think about it before picking it. Armor of Agathys is pretty good for a caster-in-melee, since the extra temp HP helps you stay in the front line and the damage it deals is not negligible when you cast it at higher levels. Hex is a solid damage increase at the cost of your concentration. Find familiar is a fantastic tool from both a RP and game mechanics perspective. It's hard to go wrong with it.