The developers could simply replicate the panther animal companion stats, but change the graphics appearance for it -- there is no real need to give it any new stats, or make it a "real" Crag Cat for the purposes of having it as an animal companion. It sounds like folks just want the option to have an animal companion that looks like a Crag Cat, for RP purposes.
You could basically do the same thing for most other animal companions -- a bear could be given alternate appearances to replicate a black bear or brown bear or polar bear, a wolf could look like a dire wolf or a winter wolf, etc.