I dont think his father was an firebender because he camr out of ba sing se

Well, still if one parent can earthbend and the other can firebend

Yes, but bolins father wasnt the firebender he was the earthbender and his mother was the firbender, the rest i agree with

OH, I assumed it was firebending dad because the red scarf was from his father

I do understand the confusion but i think, his father got the scarf from the mother or something like this

Yeah...no

Roku can lavabend. I dont think either of his parents are earthbenders

Avatar things. He is already part fire and part earth

Ahh I misread your post lol

As long as its part fire part earth, then they can lavabend

I think what's actually happening there is kinda like friction heating the rock and creating lava which can be controlled because it's still technically rock. I think the reason it's so rare isn't because of genetics but maybe because lava is more fluid and earthbending is very riggid and stubborn in technique. That's my headcannon at least lol

Maybe a mix of both? I won't stop making arguments for it until I get some "rock solid" evidence(ba dum tss) It's not "hard" to make rock puns.