Nice video on the power seat process to use a drill on those spindles. If the motor should be replaced or working again, is it simple to put those spindles back into the sides of the motor? (would they slip right back in?
Any update on removing the driver seat to diagnose the the up/down issue? Could you test power continuity of the switch without removing the seat? Maybe supply power to the motor side of the wiring harness to test the motor?