Shadow Hog
Member
Knuckles being the last of the echidnas is fine and all I guess, but having another fox wouldn't really make Tails that much less unique, unless that fox were also to have two tails for some reason and be able to use them to fly like he does - something I don't feel Sega'd be silly enough to allow to happen.Even if Penders wasn't involved, I'd imagine that lore-based reasons were good enough to keep Knuckles and Tails unique. If I recall, Miles Prower was supposed to be one of a kind, while Knuckles was supposed to be the last of his.
Anyway, I'm also sort of guessing gloves and shoes are mandatory, so that combined with no foxes means "Zootopia's Nick Wilde fights Dr. Eggman!" won't be happening anytime soon, I guess.