Small trees for a small backyard

Hi all,

I've been doing research on small trees for my backyard. It's west-facing in in zone 6 (Burlington, ON, Canada). Are there any suggestions for a tree that is--10 to 16 ft tall, up to 5 ft wide (that i can prune), full sun, flowering, needed for privacy from nosey neighbours. The 2 trees are required at the front corners (cut off diagonally) to add vertical interest also. They would be next to Goldflame spireas. I was originally thinking Japanese Maple, but with the full sun, the leaves would burn. I'm thinking about the Ivory Silk Japanese tree lilac, but it may be a little bushy. Can I prune it to thin it out? Or the Black Stockings Meadow Rue. But the Meadow Rue only grows to 7 ft. Any suggestions would be greatly appreciated.