No the cat was plain white with black paws and I had a kitten like that when I was younger. Sure it did happen but he only lived to be about 7 months old because of genetic deformities. She based it off real genetics she just didn't attach the medical problems with those colorations.
No there was a male cat with two different black-based colors. It had different colored paws. I know it is possible for a cat to have high white. I just cannot remember the cat's name. There is nothing wrong if she didn't base her cats on real genetics. The focus of her stories is not on genetics, it is on clan life and adventure.