Thanks, friends, for your thoughts. Right now things are in a holding pattern. Diva is doing okay but when I return from my appointments, sometimes I find her in distress, trying to drag herself over to her litter box but not being able to. It's kind of amazing, though, how well she navigates around just on her front legs. I'm certainly not ready to take her in for euthanasia, since she is not in pain and I am able to baby her just for a little while.
The vet said if I didn't bring her in within 24 hours of her diagnosis last Friday, I would be subject to an additional $75 examination fee on top of the euthanasia and cremation costs. That's unfair, IMO. I refuse to be pressured into ending her life before we both are ready.