Very impressive set! Are the BGs made from 3D models? Is that something you would be willing to share as well? I'm working on an unreal project that can make use of 3D models. I would be very interested! Hope you have a great day! :)
I'm sorry to say that they aren't made from 3D models but instead photos (Most of which I personally took) that I've drawn over. So I'm afraid I won't be of any help to your project! Sorry for any inconvenience!