Thank you everyone for the wonderful feedback, support, prayers, research links, and such. You've been so very kind to me.
The great news is that Alice does not have anything immediately life threatening such as a bowel obstruction, cancer, of FIP. For that I am profoundly grateful and oh so relieved.
The sad news is that my precious 7 1/2 year old innocent outlaw imp has diabetes. I didn't catch it as soon as I might have but at least it still got caught fairly early and her condition is not severe. Glucose levels are off in the minor to barely moderate degree and there are no ketones in her urine, which is very good all things considered.
The vet gave her fluids because she was slightly dehydrated from all the throwing up, gave her a shot to quiet the nausea, sent me home with the type of insulin and syringes calibrated for it appropriate for cats, a small starter batch of both dry and wet D/M diabetic cat food, a ton of instructions and assurances that this is a manageable disease, albeit one I shall have to be quite vigilant about keeping Alice properly fed, medicated, and looked after.
Right now I'm tired, feeling a bit overwhelmed, and have decided it is enough to just get through tonight and in the morning I'll set about organizing how I'm to manage feeding three different, conflicting, special diets that are polar opposites of each other, and do so on a schedule that feeds Alice and gives her shots 12 hours apart.
I have to take her back Saturday morning for a glucose check and again early next week. Until her diabetes is under control and stable I'll be making lots of trips to the vet for such checks and to make any necessary adjustments to her insulin dosage. She's being started on a small dose which will gradually be increased.
Lots of reading to do from the information I was given and several online resources the vet pointed me to. Lots to learn, lots of adjustments both I and the kitties have to gradually make. And once everything is controlled and running smoothly, I'll have to make advance arrangements for someone knowledgeable to come care for the cats in the event I have to be out of town or end up in the hospital or some such.
So, I now have 3 medical special needs cats out of 4 rather than just 2. Tigger has old age arthritis, chronic renal failure, chronic UTI/bladder/kidney infection no longer responding to any antibiotics and, as of a week ago, heart trouble. He gets arthritis meds in his food and now a heart med I have to pop down him as he eats around it if I put it in his food or a treat, and must eat a low protein diet. Mandi has IBS, has to have the Z/D food with hydrolized protein she can digest, sometimes also needs a daily anti-acid, and is prone to UTI's that need antibiotics fairly often. And now Alice has diabetes, will need two insulin shots each day, and must eat a high protein / low carb diet. So far, please let it remain so, Frisky is healthy except for an occasionally recurring eye infection and can eat anything.
Guess all that experience with managing elder care and meds for my parents is going to come in handy figuring out how to manage this series of conflicting dietary and med needs for the cats. Nice to know God trusts I can handle this but frankly I'd have been delighted to have a houseful of healthy cats instead. Oh well, I love them and that's what counts.