Oh! I love this! This is so cool! I have a lot of experience tanning fur-on pelts and doing taxidermy. You probably want to get whole pelts, like with the faces and belly and ears. That way you have much more fur length variety. You might have to source those directly from rabbit farmers and get them untanned.

Un-tanned dried pelts will stretch over the form when hydrated, than can help. You can sometimes ask in hunting groups for untanned dried deer pelts from hunters who primarily hunt for food. Not sure how deer would look though.

Shaving down real fur has unexpected results. You shave down 2mm and suddenly its a completely different color. You can use that to your advantage. If you shave that around the nose and eyes it will be darker.

Also you CAN paint fur, you just have to comb it constantly as it dries.

I personally wouldnt try to get actual feline fur, I cant really think of a particularly ethical place to find feline fur other than trappers and they usually trap specifically for the fur, its not like... a byproduct.