So that leaves:
snake pony
— Catch-all tag for “snake + pony” hybrids. All other tags imply this.
snake pony (no legs)
— Obvious in name, it almost doesn’t need a description. Implies naga
naga
— Implies snake pony (no legs)
snake pony (2 legs)
— Implies lamia
lamia
— Implies snake pony (2 legs)
snake pony (4 legs)
— Implies tetrapodophis
tetrapodophis
— Implies snake pony (4 legs)
———
You could use aliasing for the various special names, but that would ultimately make the clarified tags useless, since no one would ever find them.