I’m starting to think Eevee might be based on the common ancestor of dogs, cats, weasels, foxes, otters, etc. Sound cool? Maybe the bunny ears symbolizes it’s evolutionary leap from herbivore into a predator.
Well, the basal Carnivora probably looked something like this – much more distinctly cat-like than Eevee and probably tree-dwelling – so I think it’s highly unlikely Game Freak specifically had something like that in mind. I think conceptually they may have had ideas like common ancestors and adaptive radiation in mind – they did call her “the Evolution Pokémon,” after all. But we already knew that.