I beg to differ with you. All the transmissions you referred to have an electrical solenoid inside of the trans, that controls the fluid for the lockup. They have a electrical connector external to the trans. The 904 hydraulic lock ups do not use a electrical solenoid, and do not have a electrical connecter on the trans for lockup operation. The only electrical connector is for neutral safety and backup lights.
I was wondering if it is possible to convert the non electrical LU to electrical. That would make it easy to control manually.