As for the hair, we also don’t completely support Groom exports into Omniverse yet. As we stated in this other forum post: Metahuman hair missing - #4 by LouRohan, we don’t have it working correctly yet.
The skin material export can be addressed by modifying the Unreal material as demonstrated in the Discord channel: Discord
This video may still be correct, but the MetaHuman projects can change over time, there was a headmask function that changed in the latest version of the sample project that is not yet supported. We have an internal ticket for this… OM-46978