As far as the Sunday Morning building goes, I think three of them is a good number. To me, there is too much repetition in that painting. But, who am I to judge it. Hopper knew what he was doing.
The high angle views are good to show what spaces are open and how to move things around. You are so right to never attach a buiding to the layout. You never know when you want to move it, make repairs, or make additions.
