inb4 arcanines jumping out of tall grass, giggling

Haha, you think Arcanines could fit in tall grass rather than have even their paws loom high over it. That's cute :D

No seriously, that sounds adorable and fun <3

That grass is a lot higher than it looks; there's a cliff there.
Hm, wait, crap, the cliff would be deep enough to expose the magma of the planet. I think I just solved one problem to pose sixteen more.

I'm not sure I understand what new problems would be caused? The Arcanine would be standing in the magma, and their Flash Fire would let them absorb it all, and make them start growing into powerful deities. Seems like it's all on track to me!