Are There Examples of Additions To Levels Through Scripting?

A couple of questions. Okay I am new to Unreal 4 editing, but have done a large number of tutorials. I have also used Game Maker Studio, Unity, Daz3d, Hexagon, Bryce, Terragen, Blender, Photoshop and several other Modding / 3D game creation tools. I have much programming experience.

Two basic questions.

Is it possible to create a script that will duplicate rooms or all shapes in a level, and mirror them down a parallel plane of axis (creating a second image with all of its geometry flipped)? Probably just the vertical axis. Is there an example anyone has seen? I know there is fractal paid content. I have a tool like this for Daz3D called Kaleidoscope, and am wondering how I could do this here, or something more tweakable.
There is a ton of parallelism in the levels I am building. And I can’t just flip geometry in the editor.

Subtractive Geometry. Okay I know you can subtract from geometry, but you can’t subtract from geometry with materials? How can you subtract from pre-existing content? This is puzzling me, and wasn’t in the tutorials I went through. Ideally I would like to know how to subtract form everything, but I went through the object editor and didn’t see an obvious check box.

I have many other questions, but I think I can resolve most of them by getting more familiar with the software.