Well - I was going to call the vet today anyway and then...
Fuzzy threw up her breakfast...
So we went right to the vet and she took a urine sample which came back within normal limits. Fuzzy has an appointment on Wednesday for an ultrasound test to check her liver and they're also suggesting a liver biopsy or fine-needle-aspiration which we're considering to check for microvascular dysplasia. I can't seem to find much information about this condition, but it doesn't seem to be as serious as a liver shunt, so given the choice I guess that's the lesser of two evils. Especially since Fuzzy isn't displaying any clinical signs of either condition...
Thank you all for your continued best wishes for The Fuzz!