Hi chase, I think you need to just get in there and try this stuff. If you use one somoothing group you won't see these massive shading errors in the mip maps/lods until you use a low resolution normal map? Are there times where these errors don't matter or come up so you can use one smoothing group without worrying about…
The locking normals thing is important if you're baking in Maya, as like Alec said, if you have a lowpoly mesh that is a mix of quads/tris/ngons, and bake from that, and then triangulate your mesh normals change and that will cause smoothing errors. So you can triangulate before baking, or your can lock normals after…