Thanks to Melzinoff's help and guidance, I've re-done Dry Bowser from scratch and fixed all his issues! He now doesn't have any weird arm problems, opens his mouth when spitting fireballs, removed the script error related to a missing sound file, added in Dead Eye Texture, and made it so each of his parts are now recolorable individually instead of all being in one slot (I genuinely just liked how that looked, but it's better this way for sure).
Still has Bowser Moveset compatibility (Shell Spin, Fireball, Heavy Stomp SFX - Credit to Wibblus)
I've also replaced the Metal Shell with a Chain Chomp instead as it looks much better than the shell model.