Nope, if you fully resist the fireball, no liquid flame pool is spawned. Same with grounding totem, although it does seem like there may be a bug if the grounding totem is cast just before the fireball where the pool does spawn. Taking my time, though, and getting my ground totems up at least a second before the fireball impact, I didn't have any pools spawn on two successive runs.

I was at level 63 with my shammy 5 man team; without even popping trinkets/EM, just CL+LB spam, the dragon was dead before he got to use his flame breath or fear. And, yes, for me Vaz stayed out of combat the whole time. Could have had a smoke, bio break. But he goes down in like 2-3 LB volleys, so you don't need much mana.

I wiped on this fight my first two attempts, in that ugly way where Nazan despawns and you can't attempt it again. After I took my time with the grounding totems, I took basically no damage at all. That was a lot more fun :-)