He remembered all of our cardboard tunnels and castles. He was running around, exploring, doing binkies. The cats came down in the evening- to smell his stuff and check him out. I was worried that having him around would stress them out but they seemed to remember him. They went about their business as usual- just keeping an eye on him. There has been no sign of aggression or anxiety. Penny runs and hides when people come over to visit but she didn't do that with Rocky- she just watched him. I think it's a good sign that Rocky and his hutch are in the living room and the cats haven't been avoiding the living room- they're just staying out of his reach. We're giving the cats extra love and praise.
Now I just have to figure out how to take care of a rabbit. I've been googling every food to see if I can give it to him. "Can rabbits eat grapes?" "Can rabbits eat celery?" I'm picking up the CSA this afternoon- so I should have lots of nice things to share with him.