Hi there.
Overal I think it looks good.
Would just like to give you a tip I've read.
When using people in renders they have to match the light or like the article said rather leave it.
All your people have been photographed in daylight and in your dusk seen they start stick out very unnatural. A big mistake I've made myself. The other thing is contact shadows, again even in a dusk setting there will still be shadows albeit diffused, and unfortunately your people "float a bit"
But I can compliment you on atmosphere, renders do kinda tell a story.
To make everything much easier just make an opacity map with your 2d person and apply to plane that is correct size of human and place in scene. It will take care of your correct size and give you contact shadows. Just ensure you match render light with 2d cut out's light.
Hope this helps :)
