After hours of googling for information, I have succumbed to needing a helping hand!
Bear with me... Despite the information I was able to find, I am quite confused:

I have 4 different mesh objects, all UV unwrapped, with 4 separate baked textures, and 4 unique materials assigned. The goal is to combine them all into 1 mesh object while still being able to use my 4 texture maps on each previously single object. I understand it is possible to do this via Mesh>Combine + making sure you assign a new material to each object, which I did. I assigned 4 new materials, and even coloured them 4 unique colours. When combined, the colours/materials and UV maps appear to be preserved.

But here is my problem:
When I combine the 4 mesh objects, the 4 distinct UV maps become layered on top of each other in the UV texture editor. I can move them around by "Select Shell"... but where to move them to? Is the UV unwrap data preserved in each of the previously uncombined 4 meshes though they have now been combined? And is it the assigning of distinct materials that tell the objects to accept a distinct texture? If so, then it makes sense to me that I should be able to apply my 4 texture map files to all 4 of the mesh pieces separately even though they have been combined. However, I can't get it to work.

Wouldn't moving the shells around in the uv editor ruin the objects ability to be textured by the 4 textures I already created when I initially uv unwrapped them? Unwrapping again after merge would seem to be complete opposite my goal. I feel like I am missing a big chunk of knowledge in regards to how this works, and I can not seem to connect the dots -.-

I tried a few methods, including combining first and then selecting faces > assign new material, and the entire object keeps wanting to texture as a whole. I am unable to pinpoint if the problem is in my material application, the positioning of UV maps, or other.

Soo confused, please

Here are photos of the UV texture editor, combined & spread out