VikkiandHarold,
Your planned yard sounds absolutely beautiful. When planning, definitely plan for the maximum size of the plants when you're placing them, particularly for trees and bushes.

Dogwoods generally prefer partial shade, and Japanese maples prefer mostly shade and generally burn easily in sun, whereas Cherries do very well is full sun. You did ask for fast growers, so remember that most Japanese maples are sort of slow growers. I'd stay away from river birch because I've read that they have a very short life expectancy in our area, for whatever reason. I have two dogwoods (they do get powdery mildew in the summer), an eastern redbud, and a kwanzan cherry. Given your space limitations, I'd stick to plants that grow taller than wide, unless you have powerlines to deal with. To hide my neighbors balcony which looked over my yard, I planted a row of mature privet shrubs that I hope will grow at least 15 feet tall to block their view. Regarding shrubs/potted plants, in a small urban yard, I'd choose things with lots of color and flowers. I love the newer varieties of hosta, heuchera, and astilbe for shady areas. You can fill pots with annuals or tender tropicals like canna and caladium that you need to bring indoors during the winter.

well it does sound like a nice place to play plants there..it's an eveluition task though .. things will not do well and are replaced.. and then you get to by more ..
the river birch is interesting... chew on one of the small /twigs..and you'll see why they thought to use it in making BIRCH BEERone thought for you.. is if you're raising one end up a few feet... it sounds like a lovely place to drop in a planter or two .. with the soil line being even with the decking.. it would give an ongrade look to it.. and provide some good known soil to grow something out of... backyard soil is often of poor quality.. unless it had been an improved planting area before .. lots of building debris has made it into the back yards with a bit of soil over it.. be sure to improve the tree planting sites... remember the old saying... dig a $20 hole for a $10 tree