Wow Lindsay, what a great start to your orchard!
I think I would want to include some nitrogen fixers in the tree and shrub layers. You have lupine for your herbaceous layer and clover for your ground cover layer. I would consider seaberry (Sea Buckthorn) for your shrub layer, which not only fixes nitrogen but produces a medicinal berry. The black locust is a great option for a nitrogen fixing tree in your area. Although, black locust does not offer a food yield, I've heard of people using them as scaffolds to trellis grape vines. My understanding is both of these nitrogen fixers grow quickly and don't need much attention to get going.
As for timing of your harvest, chestnut, hazelnut, apples, and pears are all late season crops. Cherries and plums are typically mid season. I would consider including some early variety apricots and peaches to balance out the yield of your tree crops.
Thank you for letting us share in your orchard design! Keep us updated!