I'm not an artist - my 3D modelling experience can be summed up as "none", so I can't really answer your last point. I know for certain that we don't use normal maps to the extent they could be used, and therefore have way more detail in the meshes than they would need to have. I'm also pretty certain that we don't do any tesselation on player pawns, and I think (but am not certain) that this is due to some engine limitation (again, don't quote me on that, but iirc Unreal doesn't support tesselation on skeletal meshes on all our target platforms).