An observation (that doesn’t answer the question at all, I’m sorry): I think choosing one best background is hard because the house tops aren’t consistent in where the light/dark values are. Sometimes the housetop is dark with light sky, and sometimes the housetop is light with a dark sky.
By contrast, it looks like the house bottoms are consistently dark house on light background. For me, this leads to some visual confusion on reading the houses against the background.