Though I always wondered, the difference between Earth Rabbit Youkai and Lunar Rabbit Youkai. Would it be an ethnic thing or genetic thing?
Earth rabbits start as normal rabbits and only occasionally become youkai, whereas lunar rabbits seem to be always humanoid (or at least we've never seen an animal one). Plus the lunar rabbits have presumably been isolated up there for about as long as the Lunarians themselves, so there'd probably be some changes in that time even if they started out similar.