I don't think this is really that important in your case. You are planting trees from seeds, and only for shade and ornamental purposes. Your resulting trees will have wild apples when they fruit. You still will have flower blooms,,,, which is the beauty of such trees.
If you did decide to get apple trees from a nursery, those would be a variety as labeled, but would be as a result of grafting. That is when you would consult the chart to determine which apple varieties to purchase. Also how to plant, and space.