Oh wow, way more motion! Nice!
Would be cool to see your new fascia, and also what the sim looks like from the back.
To get back to the skin, one way is to have a separate file that takes:
- An alembic of the fat bake
- An alembic of the skinClustered render geo from original anim (for head, hands and feet)
Then just wrap a copy of the render geo to the fat.
Make a blendshape between that and the skincluster alembic and paint the weights of the blendshape to blend the two meshes together.