I'm pretty sure blue flames being directly hotter than orange/yellow is sort of a misconception (but that's still off topic).
Anyways, I think both these moves would be great additions, but I don't think blaze needs to be replaced by them (if anyone is unsure whether or not blaze was actually used in the show, I'm pretty sure its supposed to represent Zuko's firebending breakdancing move where he sweeps his legs across the ground, lel).
I don't think having more than 9 moves is a bad thing either. Having more than 9 possible attacks to use brings diversity and strategic choosing to everyone's unique moveset (plus fire and water both already have 10 moves).