Retarget the mixamo animation to Manny and MH, then in sequencer start all to walk at 0000, set transform location keys to move to say 100 , then turn and walk back using transform rotation, I have a test project with the original mixamo figure, Manny and the MH. The mixamo figure and Manny both turn and walk back to their original 0000 position. As soon as I apply the turn to MH, at 0100, the rotation transform is applied all the way to 0000 and the figure is locked in place walking/running in place, but faced the wrong direction
I’ve tried ignoring the MH rig, muting and deleting it nothing makes a difference.