Update on Maggie.
Went to the Vet on the 18th, they took blood and urine and fecal and several other bits, tested them thoroughly. She has an infection on her nose, between her eyes, sorta - this is clearing up with antibiotics now.
The other issue, however - the blood in the vomit - is harder to diagnose. There was no urinary tract infection, her thyroid levels are near-perfect, but her liver enzymes are 7x normal. Function is normal, however, just the enzymes that result from liver cell death are high. This means the liver is working itself to death trying to purify the blood. We have known for a while that the steroids were all that was keeping her going - 10mg per day is a hefty dose for a 28 lb dog. The steroids depress the immune system, letting infections take root, thus the antibiotics. The infection on her nose could cause the liver issues, but the vets seem to think there might be something else going on.
So today I have an appt with the specialist that handled her surgery last time, to see what can be done (if anything) to correct her liver issues and keep her with us a bit longer. I won't put her through another surgery, however, so I hope there are medications that can resolve this or that her system clears itself and the liver goes back to it's normal ranges. Maybe the antibiotics will be enough. We'll see.