We all spend the night with no one locked up last night. Kaylee woke me several times not knowing where her food and water were and the last time because she REALLY wanted to play while I wanted to sleep. Nate no longer hisses. I think we have good integration, though Nate's still kind of grumpy, I think, and feeling unloved, not that I don't try to love him.
Here's a video of Izzy letting Kaylee play with her tail. I can't say she's thrilled, but it's quite the sign of tolerence.