We had a supervised visit between her and the P-Man this evening. We put him in my room and let him sniff all around, and took her on a guided tour of the apartment. She seemed nervous but not panicked, so we kept her in arms while she met our other roommate and looked around. The cats saw each other on the way in and out, each held by one of us. There was no hissing or growling, which after just a few days, seems like a really great sign. We will give them another supervised visit tomorrow night and see how it goes.
Pretzel seems a little bit off today. He's been sulking a bit (lying down pointedly with his back to us and his fur up), hiding under the couch a bit, and didn't eat all his food. Some of this could be side effects from him getting into the kitten food yesterday while we weren't watching. Whoops! At other points he's been very active, so we're not very concerned yet - just cautious. We're playing with him a lot and reassuring him a lot so he can see his new roommate as a positive thing. A little stress seems reasonable, and he doesn't like the heat much either, so it may not be anything serious. Hopefully all will continue to go well.