Creating a Game-Of-Thrones-Intro based Map

Hello everyone.

I am currently programming an RTS-MMO game and my graphical concept was inspired by the Intro of Game-Of-Thrones. If you scroll down on this page you see a lot of images that show what I mean:

But I try to break it down in a 3D-Moddeling wise way: only horizontal or vertical planes, where all horizontal planes have a different texture.
Now I am unsure how I could make such a map. I am working with blender and that is what I came up with so far:
Now my questions:

-Do you have any idea how to make the process of making new “faces” more easy? Currently I go to Top-View, set all points manually, then select all, connect and then extrude them. I wonder if there is any more efficient way of doing it.

-Second but more important question: How would I apply textures to this map, where every “plane” has its own texture, optically? I am working with Unreal Engine 4, if this would be possible in either Blender or UE4 I would be very glad. Are there methods to texture-paint only a single face, without having to make it a own material, since Blender only supports 12 Materials, I believe.
Also there seem to be some problems with Blender to UE4…

Every response is very appreciated

Greetings from Germany, Sebastian.

I imagine this would be a lot more efficient to use something like world machine. Or any heightmap editor.

You could render your current model as a heightmap, place it in world machine, set the selections to be based on height and export those.