All those tiny blue plums from David Kemp have turned out to be Blue Damson. It's an old heirloom variety that isn't popular because they're so small, but they're the traditional cooking/canning/kitchen plum in the American east. They don't do well in the grocery store because they're so small, but that shouldn't concern us.
Louis Van Horne has a larger blue plum that has volunteered next to his driveway. I do not have time to fool with it this year, but next year it would be a good one to plant or make cuttings from.
He also has those peaches.
None of these are cuttings, so there's no easy way to tell what will come up out of the ground from the fertile pits, but I suspect we'll be okay. The key is that all these trees are producing heavily with no pruning, no spraying, no fertilizing, no watering, and no specific care of any kind, in this climate.
Pity you can't eat Osage Orange. There's one up on the ridge road doing very well.
By the way, I scattered several hundred Blue Damsons in the beeyard, and across the road along the fenceline. I don't know whether any will survive the Microtines, because they will spend the winter under the snow looking for seeds and pits, and the early spring eating the bark off any that come up. I have another bucket of Blue Damsons that I want to plant in an open-bottom frame so they can chill over the winter, and those may be the only ones that we can use.