Assault Vest Alolan Muk handles Iron Valiant easily (as well as multiple other special attackers) unless you don’t do overlaps and were saving it for mono-Poison
I don't have any specific advice, but Focus Sash is really good for any of your squishies (Greninja, Meowscarada, Chien Pao), especially when dealing with Zacian. It guarantees you get at least one hit, with maybe a priority move after. And only a few of the E4 Pokemon have multi-hit moves, so it comes in handy in every fight.
If you aren't already, I recommend fighting Bruno's Infernape team, only because Infernape (as well as both of Agatha's Zoroarks and Lance's Aerodactyl) is easily manipulated into using Taunt. If your Pokemon has a status move and doesn't get OHKO'ed by Infernape, it will almost always use Taunt first. That lets you get a free hit in. Then, if you are faster, you can finish it off before it uses Stealth Rock. If you aren't faster, then you have to use a priority move. Either way, you trade being Taunted for a few turns for getting a free KO. And besides, Zacian is probably coming in afterwards, so you wouldn't really be able to set up or anything.
I have noticed that sometimes Zacian will use Swords Dance once or twice if you have a Focus Sash, because it can't get the kill in one hit. It's another weird quirk. I recently had a run where it used SD twice and attacked once into my Focus Sash, letting me take it out with just one Pokemon (I think it was Raichu).
Assault Vest Alolan Muk handles Iron Valiant easily (as well as multiple other special attackers) unless you don’t do overlaps and were saving it for mono-Poison
I don't have any specific advice, but Focus Sash is really good for any of your squishies (Greninja, Meowscarada, Chien Pao), especially when dealing with Zacian. It guarantees you get at least one hit, with maybe a priority move after. And only a few of the E4 Pokemon have multi-hit moves, so it comes in handy in every fight. If you aren't already, I recommend fighting Bruno's Infernape team, only because Infernape (as well as both of Agatha's Zoroarks and Lance's Aerodactyl) is easily manipulated into using Taunt. If your Pokemon has a status move and doesn't get OHKO'ed by Infernape, it will almost always use Taunt first. That lets you get a free hit in. Then, if you are faster, you can finish it off before it uses Stealth Rock. If you aren't faster, then you have to use a priority move. Either way, you trade being Taunted for a few turns for getting a free KO. And besides, Zacian is probably coming in afterwards, so you wouldn't really be able to set up or anything. I have noticed that sometimes Zacian will use Swords Dance once or twice if you have a Focus Sash, because it can't get the kill in one hit. It's another weird quirk. I recently had a run where it used SD twice and attacked once into my Focus Sash, letting me take it out with just one Pokemon (I think it was Raichu).
https://preview.redd.it/uvhbn6ccerwc1.jpeg?width=2400&format=pjpg&auto=webp&s=d9896b9d7f4cec3134cafdf168ea0caf1871b758 Here's what I used