Re: OOC (Clarifications, Etc.: Second Incarnation)
Cheetah Person?! 'You're nothing like my Puddy!' Actually, they'd have a lot in common, since Kangs basically boil down to running and hunting, but I'm not sure Smoke would accept one, not at first.
It could be like Ace sometimes is in books, audios, and the Doctor Where? game: normal most of the time until pushed and the Cheetah aspects come out. If you can find a way to turn back, you might even go full were-cheetah, which is basically what the Cheetah People are.
They could talk, Kara talked a lot with Ace while in full costume.
Interestingly, writer Rona Munro suggested they'd be human-looking with some cat-like make-up, which would've been quite cheap to do. Except the costumes came back as all-covering suits and cat masks. She was unhappy about that, as it obscured the lesbian subtext between Ace and Karra. ;)
The Seventh Doctor era is odd like that. The Kandyman was meant to be odd-looking humanoid in a labcoat, not a massive candy robot; the Destroyer a creepy guy in a suit, not the best demon costume ever. So, by the time Who writers had finally figured out to suggest things subtly and economically, the designers had finally worked out how to big amazing costumes.