I am in zone 5 and I am planning to plant 2 Gold harvest crabapple trees in my backyard. Any pros and cons? I saw these trees at walmart for $24.00. Can I buy from them or should I only trust a local nursery?

Also, any suggestions on kwanza cherries, dogwood or any other better trees? I am a newbie so get confused about picking the trees/shrubs.

Also, any tips on what to plant just along the side border of the house facing east-north, so the sides are north and south.

Thanks a bunch.