I had 5 crepe myrtles planted in a row, 3 feet from my house much like yours. Not by me but the original owners. I tried for many years to grow them vertically. They did grow uo over the top of our house. But they were terribly miss shapened. And they cligged my rain gutters.
4 have since been removed. These are full size trees and grew leggy and weird with the 2-story house behind it. They left one on the corner of the house as it has more room to spread which it has beautufully. Planting in a wide open space where yiur new trees can spread in all their glorious beauty gets my vote.