Hello Tarotbear,
Actually, I do own both those decks, although I don't use Tarot for Cats especially since I found out it was out of print. As for Tarot of the Cat People, I agree, that it is really meant for humans, although I have used it for "pet readings".
Sometimes, however, I want to know what is going on with my pet, and believe it or not, some of my clients want to know about their pets as well. I have a pet spread that I use and that of course answers any question. It's just that I believe I read somewhere that if you want to use a significator for a pet, you may want to use The Moon and the Fool regarding dogs, The Queen of Wands and Strength regarding cats, The Sun and The Chariot regarding horses, however, I don't use any of these as significator cards. Let me point out that it is not a matter of life or death if I don't have a significator card, but I sometimes use a spread where I pick out a significator card and put cards surrounding it to see what "surrounds" you.
My pet spread is different, perhaps I'll post it up next time.
Lots of love, Misifu