I would make those wood planks have a higher polycount and some more vertical lines on that middle section there are only horizontal lines. But the model does look pretty cool
The UV number should be closer than the vertices number. If your hard edges are the same as your UV border edges, then, UV number in maya should match verts number in Unreal.
Go to Reflection or Secondary Reflection ( More parameters to tweak the anisotropic). Here: Remember to put your hair cards vertical and straight to have a working anisotropic shader at aprox 90º direction.
"divided in 1000 islands it doesn't matter." It does matter because you are creating extra vertices. Seams can also appear along UV cuts from mip mapping the textures.
Basically you want to wires on the shirt to match up with the belt enough that it will animate well. They don't need to be exact, the main thing is you want vertical edges in roughly the same place.
Think of it like baking a normal map to the vertices. Any time you need to completely avoid texture compression or interpolation artifacts you should consider using vertex attributes instead.
Could it be unmerged vertices or double faces or something like that? I usually check for such things by hitting 3 for a smooth preview and if it doesn't smooth as it should then that's a good indicator that something needs fixing...
Didn't photosource it. I used the dodge, burn, and paint tools. Should I turn the grunge layers vertical? Or should I turn them off? For the highlights, what's the best solution?
Better to not add the inside surface at all. Only extrude at the openings, after you bake, and only what you can see. Unseen vertices are a big waste, runtime memory is precious.
This thread has the answers too. You can add vertical loops like steppenwolf said, or you can bake a normal map. http://www.polycount.com/forum/showthread.php?t=135895