Let me explain my thoughts about Heatproof a bit more:
Astrolotl is clearly inspired by outer space and fireworks, between its design and its name. To me, that suggests that it can enter and leave earths atmosphere at will, which is where Heatproof comes into play. Spacecrafts and...
I think Heatproof would make a lot of flavor sense on Astrolotl. It’s a firework/cosmic dragon thing that looks like it would enter and exit the atmosphere, and Heatproof would make it nearly invincible to Fire (which would have very little practical application considering it already 4x...
A combination of "Ryu” and “Fusillade.”
Ryu is a Japanese term for dragons, and fusillade is a general explosion or discharge, such as a firework exploding, cannon firing, etc.