I see they're looking over their shoulders, just checking for that "dumb" dog...LOL. My cats' expressions seemed to be more of....."hey, who said we needed one of THOSE? What's wrong with just a kitty house?"
They may become friends and they may not. I've had it go both ways. I don't think Trace is friends with mine, but they've accepted that he's here. And they figure a little swat now and then, just lets him know....they can "take" him "out" any time
My youngest cat does play with him a little bit, but he's the only one.......and he definitely doesn't let the other cats SEE him do it