The issue with the giant afro-like hair was an issue with using SetVisibility and propagating that to the hair components. Some of the hair has that issue when be toggled that way. SetActorHiddenInGame can be used fine instead.
In case anyone facing these issues also has the Assertion failed: Instance->Guides.DeformedRootResource->IsValid(MeshLODIndex) crash I have, hiding the actor and immediately unhiding it in the MetaHuman’s BeginPlay event fixes the issue.