I can't really help, but I look forward to the responses you get.
I'm experimenting with growing pawpaw from seed way up north out of their range. I let about a hundred seeds germinate in a bag of damp soil until late spring when I planted them out into four 1x2 air-prune beds. It seemed like nothing came up and I thought the whole thing was a loss but then in early October, I was going around the
yard, getting things ready for winter, and those boxes each had tons of little trees coming up. So I weeded out the competition, built a sheltered nursery out of
hay bales and let the snow cover them. In a few weeks, I'll pull them out and then start watching for new leaves to grow and hope that at least a couple of them survived the winter. I figure I'll plant out anything still alive at the end of summer, but might change that based on what I read here.