First an update on Isaac. He is doing well. Doesn't seem to be having any pain and his tail looks great. He is very active and we did three mile hike today. The weather was gorgeous and his only regret was that he wasn't allowed to run off leash, due to needing to keep his tail clean and dry.
This evening he began acting like his tail was itching. I think it was itching and not hurting because he would be busying doing something else, dozing or playing or whatever, and suddenly spin around and begin licking or chewing furiously at his tail. However, the incision looks great, nothing to suggest he might be having increased pain, and also he wags his tail enthusiastically and even thumps it loudly against the walls and furniture, which I don't think he'd do if it was sore. Plus, when I had staples in my arms, they itched a lot.
I checked with a veterinarian friend of mind, who suggested giving him Benadryl, so I did that. It seems to have helped a lot. Shortly after taking it, he went to sleep and is now sleeping soundly.
And an update on Hobbes, the visiting kitty. She is now settled in to her new home and seems to be doing very well there. She decided she liked a particular kitchen cupboard, so her new people let her take it over as her own room. She has a little bed in there and her very own food and water dishes, although she comes out to drink from the communal water dish as well.
A couple days ago when no one was home, Hobbes decided the dog bed, which was in a nice sunny spot, looked comfy and when everyone returned home she was sunbathing there. She says the dog bed is hers now, too, when she wants it. So she is a happy kitty now and I am happy for her.