I just realized that I'd never given y'all an update on Maeve. So after consulting with her regular vet, we had an hour long conversation, we decided that there's nothing really to be done. The problem is she's a puppy and is still growing, so for her continued development she needs the hyper-nutrients of puppy chow. Normally, an adult dog with her condition would go on a renal healthy diet right away. But the low mineral and protein of a renal diet could stunt her growth...
The slim (and I mean vanishingly small) hope is that one or both of her kidneys will grow larger and assist her in cleaning the nitrogen and urea from her blood (currently, her levels are measuring 2-1/2 times normal). For the foreseeable future, our only available action is to keep an eye on her appetite, thirst, and activity levels. If any of those drop off, we'll have to address the symptom at the time. Well, and just to love and enjoy her company. It took Mrs. P and me about a week to come to terms with having the Doom of Damocles hanging over our heads and to really engage with Maeve in good humor.
So far, she is happy, active, cute, and loving. She makes me laugh every day.