I suppose I owe you an update by now, since it's been a while. Between being busy and being ill (illness being the latest in delays) I haven't had much time to type up a blog post. However the antibiotics have kicked in and I think I'm up to at least offering a brief update on what has been going on.
Firstly, Simba's cystitis seems to have subsided for now, which is a relief. It isn't something that's serious or fatal, but it does cause her pain so of course I hate to see her like that. Thankfully my vet does not seem bothered at all by my requests for news on possible new treatments every time we're in his office. So far it still looks like Diazepam is her best option, though it only really treats the symptom and not the disease.
Simba has stopped hissing at Anubis almost entirely. She will still hiss every so often if he startles her (or runs over her when he has turned the hallways into a racetrack), and we had to chide her for hissing at him the other night without due cause. Well, I'm sure she considered it due cause - we had a large cardboard box sitting in the living room and she decided it belonged to her, and her alone. That was quickly corrected and she (perhaps a bit grudgingly) learned to share.
Anubis is now frequently found asleep on the bed. He and Simba seem to trade places - one on the bed, one on the cedar chest. On rare occasion they will both be on the bed. They have yet to curl up together, but they're coming closer.
It seems they have come to some sort of agreement about acceptable play, too. Rather than pouncing, Anubis has settled for playing something that looks like tag with her across the house. One cat will start poking at the other, at which point the second cat will take off running. They usually only chase back and forth a couple of times, but we're making progress.
All in all they seem very comfortable with each other now. Simba even uses Anubis' litterbox and drinks from his water bowl. I'm pretty sure I've caught Anubis eating from Simba's food bowl once or twice. He regularly goes into the bedroom, she regularly goes into the office - before they were very wary of entering each other's "safe zones". And sometimes when James and I go to sleep at night, Simba retreats to the office and curls up in Anubis' cat carrier, with him sleeping on the chair nearby.