Final autopsy: not enough bees in the hive, they were doomed from the start. I found one bee with a mite before I emptied out the bees. Total weight: approximately 10 oz of bees. Not even a pound. After scraping all the bees out, I screened them for mites. Unfortunately this included all the bees off the bottom board, which would then include the mites killed during treatment. I would estimate I found around 100 mites..... not enough to kill off the hive....
So, not enough bees to stay warm so the cluster would not move and they starved/froze. Will do better next year..... I think chickens have to be easier!