Update. Most of this already went into an emergency help thread, but I like to keep this thread up to date for my future history lessons.
It's a little chilly today, low to mid 50's. Sparse fur, an extra layer of hay, thought they'd be ok. Had to go out of town. Back around 5. Kits cold to the touch and moving less than this morning. Into the bathroom with a space heater, the weakest three under my shirt on my belly in the recliner. Couple hours later, bathroom bunnies squirming like crazy. One in my shirt squirmy. Two Warm, but lifeless.
They're back in the nest box. Base of synthetic cotton, extra hay, every scrap of fur I could collect. Not ideal, but out of options.
Mom immediately went into nest box, but not long enough to nurse. At this point, que sera sera.
Mom is history. After weaning, or as soon as I have time if the kits don't make it.