How to make Mixamo model face realistic -- fuse Face Builder mesh at the neck?

Question

I'm trying to recreate a historical figure in Blender.

I recreated his face using Face Builder, and have downloaded an animated body from Mixamo who I'm going to create Victorian clothing for.

Is there a way I can make the face on this Mixamo body realistic like what I made using Face Builder, either by attaching the Face Builder head mesh onto it, or through some other process?

I thought of simply deleting the head mesh from the Mixamo body, and joining the Face Builder head onto it, but the Mixamo animation doesn't 'connect' with the foreign head...

Answer 1

Set the armature to rest pose, make sure that both head and body meshes have the same rot and scale values (if needed, press Ctrl A > Apply rot and scale).

Select the new head, shift select the mixamo character (it has to be the last selected, "Active" object, outlined with yellow, not orange), press ctrl J to join them.

Then go to edit mode, search for the "Head" Vertex Group, select all new head vertices and click the "Assign" button.