Animation, rigging, Where should I start...

I wanted to make a more custom character mesh. Add in some of the cloth effects (which look really easy in the tutorials of course)

So I cheated a bit and just exported the manni into blender and drew some clothes on him, applied UV and materials to them.
Result for the character was acceptable to me

(that’s about the view distance with expected platfrom as mobile, so he didnt even need a real face or anything)

The problems I am having though are:

I tried taking out a lot of the original mesh, and just attaching the bones to the current one. This “worked” but of course the vertecies that it was weighted to are gone and results were nit crazy as things like the calf became attached to the shoulder (!?!?!)
Having multiple save files I was able to in a matter of minutes just reimport the manni to blender and attach the clothing directly over it. This photo is that. Ue4 Mobile Manni with clothing meshes stuck on top.

When I import it back into UE it gives me a warning that there are bones missing etc. (it’s a really long list) and says it is attaching to root.

I really expected to just be able to attach the HeroAnimBP to this mesh and them all work (especially after I painted all the other stuff as cloth)
I followed clothing tutorials and left places like shoulders pink just like they did, but even just putting the mesh out with wind it doesnt move

the mesh doesnt use the animation at all (weird bone stuff i guess)

So…where do i even START on learning how to actually do this right?
Can you give me some of the specific terminology, links to youtube videos, and if there is anything I can do as a quick fix to make it (mostly) functional i would appreciate it all