Yeah no problem. The terminology "back feeding" made it sound like I had 2 sources of power to my rear camera. I am simply using the red wire attached along side the RCA cable to provide 12V from the head unit to the camera power wire as its source. I just grounded the camera ground wire in the back. No trigger wire needed with the Android aftermarket CAN bus adapter. It knows when reverse has been selected.
I power the rear cam all the time the car is on so I can record the rear image along with the front image as dash cam features. I can pull up and view front or rear live camera videos or browse through recorded videos at any time through the DVR app.