Thanks, everyone, for your comments. This is definitely one of the more challenging feline situations I've had. We have a litter box in the bathroom which is helping a lot, and Happy Kitty Nerve Gas is spewing through the house (apparently it can take 4 weeks to take effect).
It isn't all doom and gloom Chez Feline Central.
Fred shoved herself into a shoe box, then she took a nap. Look at that little face -- she is so worth all the pain (Judy is, too, it's just harder to make a case for her).
Then Fred and Gwen took in a little cat TV. By the way, Gwen is not a large cat, she's about 9 pounds, but a good portion of that is pudge, otherwise she is pretty short. She is quite neurotic, but in an interesting, quirky way (as opposed to a Kill-the-Kitten way), I'll be interested to see how she reacts to the nerve gas.