Automatically almost always goes to lod0 - depends a bit on how you set it up, but bottom line is you have to do the work anyway.
If you really have to use metahumans, it is probably preferrable to edit the skeleton itself than to use LODs.
Theres 0 need for the extra bone data to even exist (think in terms of both disk space and memory usage).
Particualrly true for animations, since additional bones include additional animation data that’s loaded and then not discarded if the bone is not present.
The LODs should have material/mesh differences btw. Like the eyelashes being cards with transparency or being physical meshes.
So having less bones on LOD0 can probably increase performance without loosing/missing out on some possibly important stuff for in game cinematics…