Drivers Rear Door Will Not Unlock with Keyfob or button

That's almost certainly a bad door lock actuator. You can check it with a test lamp placed across the actuator connector, if the lamp lights for a second or two each time you work the power lock switch, the actuator is bad. If it doesn't, there's a problem with the wiring for that door. It's unlikely to be anything else, the rear door unlock circuits are usually common at the BCM.