Update this morning:
Bumble threw up last night, after holding two tiny meals and her ursodiol down for a couple of hours. She was obviously just exhausted, weak, and overall not feeling well. Hubby stayed up with her most of the night to keep an eye on her, and I took over around 4:00 a.m. We decided against steroids, I'm just too afraid of them with her kidney and other issues.
Took her to the vet this morning at 8:00 a.m., and the vet really didn't agree with my "no steroid" decision. He realized I wasn't going to be easily talked into it, though he kept telling me he thought she would die without the steroids and might die anyway (I realize that, it's a hard decision to make).
They drew blood first thing, and I waited there for the results. The GOOD news is that her BUN is down (over the past few days it has gone from 169 to 165 and now this morning to 111), but her creatinine didn't move again (still at 2.2). That's okay, I'll take that. Not great, but could be worse. Her ALKP and ALT are coming down (ALKP was over 900, and it's 703 now, should be 150 or less so it's not great, but it's moving in the right direction). The BAD news is that her phosphorous went from "over 15" (out of range, couldn't be measured) earlier this week, to 11.5 a couple of days ago, to "out of range" again today. SIGH. Oh, well, I guess you can't get everything resolving at the same time. The other BAD news is that her HCT worsened considerably, and the vet is currently giving her a blood transfusion. On 12/3, it was 35%, 12/18 it was 26.68%, and this morning it was down to 18.48%. Vet felt that level of anemia was dangerous so he immediately suggested transfusion, and I didn't argue. I've never had a transfusion done on one of my babies before, but now I'm hoping a LOT of her general depression and lack of energy may be from that. The cause of the anemia may be a problem to pin down, but I agreed we needed to deal with the immediate issues.
Considering the blood work, the vet feels her liver is FINALLY responding to supportive care, perhaps, and now agrees NO STEROIDS, pending further bloodwork, I'm sure.
I'm worried about the anemia, but as for the rest of her numbers I'm a lot happier. I know they're not great numbers, but I'll take an improvement over the continuing worsening we've been seeing.
Diana, thank you for taking the time to give me all of Scooby's information. I know we may not be as lucky as you were with him, but it definitely gives me hope that we're moving in the right direction in trying to stabilize her. I'm so glad he's doing well!

Yorkies are just amazing little guys, full of joy and love, and I feel so bad for ANY of them being sick. I'm really happy to hear Scooby has been doing so well for quite a while now!
Everybody kiss your little ones for me and Bumble, and barring any more problems, we're on a course of treatment to keep her stable until her little body can recover from this. I know she might not recover, but we're very cautiously optimistic with the improved numbers (assuming this new problem of anemia doesn't mean something else is drastically wrong).
Dana and Bumble (who is rapidly losing her patience with being hospitalized daily)