Nice write up. I grow Franklin Cider as a late hanging/slow dropping deer food tree. They’re inedible to me, but the brix on mine run right around 20-21. Deer certainly like the fruit.
Just an FYI…USDA zone 4 has -20 to -30 winter lows. I’m listed as 4a but experience 3b (-30 to -40) lows every few years.