You can import your own clothes and body parts into fuse, BUT you need to use their topology and their predefined way of UV-mapping. They have tutorials about that on their site.
You can also import your own clothes into makehuman and apparently make your own sliders/morphs, but I only used clothing import myself.
Err… I believe you’ve missed a button somewhere. Or a whole bunch of them.
See attachment for examples of makehuman models. Those use default unmodified makehuman materials and textures.
Not perfect, but I"ve seen MUCH worse. Definitely can be used in the game engine after a bit of texture painting.