I was doing some testing this eve and using tight fitting clothes, the mask method didn’t work for what I was doing as the waist band and stomach was on show and the slight difference in mesh wasn’t easy to mask out. I have found that if I export both the body and face animation to blender along with the full body preview mesh, I then transfer the weights of the full body preview to the face/head, this is done because there isn’t the correct weights in the face to use the full body. I then make sure the armature for the face is the same selection as the body and export face, body and armature.
Back in unreal this becomes my new full body preview which I can attach to my body animation and get the face to follow the original face. I can then bake the animation which works perfectly.
I haven’t tried it in Marvelous yet as need some sleep but basically you’re creating your own preview mesh which I think the MH body is weighted slightly different from the preview mesh that is supplied. I’ll try it tomorrow and give you an update with a run through of how to do it. This looks as if it should work and be more accurate though.