Ok guys, I know it has been a while since I was here. So I thought that I would just chime in.
First, I need to go back and edit my original post. This write-up is only to be applied to all 2011-2012 Leafs. It, for the most part, is slightly different to that of the 2013+ models. I have successfully added an Audiovox camera like the one I used in my write-up in over 5 2011-2012 Leafs with no problem.
Second, I did successfully a rear view camera using all of the OEM equipment to an 2013 SL model that did not have any rear view camera or all around view. I used the parts list from that one post that someone did with the OEM part numbers. I did NOT need the actual rear hatch harness because that SL already had the 4 camera wires and connector at the hatch where the camera would plug in to. The very first time I put the car into reverse, it worked like a charm.
Third, on the same car above, I tried to wire in an after-market Audiovox camera, the same one I used on my write-up. I hard-wired the camera to the connector at the left rear C-pillar. I could NOT get the camera to give me an image on the display. I even tried a second camera with no luck. But the second I connected the OEM camera back up, it worked. I do not know if there is something behind this or not, but nonetheless, it did not work until the OEM was hooked back up.
I am trying to get my sales team at the dealership to try to let me add an OEM camera set-up to an SV model, at their cost. The moment I do and have results, I will post here for sure. I think, at this moment, the best option to adding a rear view camera to any Leaf would be to go the OEM route. The parts alone cost me about $240, which includes the camera, hatch handle, and all wiring. I think that this is the route to go for ease of install and OEM look.
As soon as I have an answer, I will post up here.