Let's keep things simple. Mature trees and shrubs do not need additional fertilizer once established so just mulch and water the first year. All the plants you mentioned can use the same general purpose plant food. I recommend a slow-release plant food such as Osmocote following the instructions on the label. So, for your potted trees and shrubs maybe half a teaspoon in the spring depending on the size of the container. Once these seedlings are transplanted into the ground, I would not fertilize them at all assuming you have normal soil with some organic matter.  I love that you are growing volunteer seedlings of your Rose of Sharon and Redbud. Be sure to keep the soil slightly moist, not wet with good drainage. Sounds like you will have a beautiful garden soon. Keep growing, Marianne Binetti