Have you checked all the fuses? I’m not sure if your model/year has a Rear Electronics Module (REM) with an associated fuse panel or if the rear accessories are fed by a fuse panel further forward in the car. But your rear door locking issues sound a lot like the problems I was having when my tailgate wiring got pinched/severed/shorted up inside the LH tailgate hinge. This led to blown fuses and rear doors that wouldn’t lock, along with other failures including the gas door wouldn’t open in the gas station until I popped a new fuse in.