I don’t know how easy this would be to implement in the current workshop but it may be good to consider for the future. Instead of relying on the current rigging method through blender, have a humanoid mapping option in the workshop editor where you can map the bones from a custom rig to the requirements of the TU rig and as long as the custom rig includes the root bone.
Not sure if it would be possible just yet but may be a good idea if it could work.