I can’t see how the Control Rig (Content\MetaHumans\Common\Common\MetaHuman_ControlRig) is attached to a specific Metahuman poject BP (\Content\MetaHumans"YourMetahumanName"\BP_“YourMetahumanName”
If anyone have an idea …
Note: I name a “Metahuman project” a project in which is imported a Metahuman created from the Metahuman Creator platform. Not epic’s Metahuman project provides on the Epic Marketplace.
Not sure if this is what you mean, but if you open the skeletal mesh that is associated to your Metahuman body then in the details on the left hand side you can scroll down or search rig, then you can attach the Metahuman control rig to the skeletal mesh here.