Lighting build taking ages and another weird issue

Another thing, is it a good idea to have all of my character’s parts attached together? I’m guessing it is as it’s kinda needed for skinning/rigging everything together. But when I see the entire mesh in Max/Maya or Unreal, all the UVs are overlayed like this:

I just hope this isn’t affecting the light baking negatively. It’s complaining about my character having overlayed UVs too. I offset things like one of the eyes and the opposite hands/fingers, but it’s still complaining.