For sense of scale house itself is enough, you don’t need people.
I looked at your file.
-Do Not use pro light sky, it’s like the worst addon ever (don’t know who came up with idea of half sky black). Use regular free hdri maps from https://hdrihaven.com/
-use regular glass material. In principled BSDF set transparent to 1, color to all white and roughness to 0. You don’t need fake glass for exterior scenes
-for fasade use voronoi texture and bump map, not displacement.
-for quick fix of the imported mesh select all object, enter edit mode, set vertex select, select all, hit x -> remove doubles, then x again - > limited dissolve. (multi edit works only in blender 2.8)
Limited dissolve can destroy details so be aware.
- for grass use this addon: Grass Free
- for backdrop trees use emission with strength 1 instead of bsdf shader