Sorry for the no update, I have the camera extension working great!
After researching a bunch, I settled on Deustch connectors for waterproofing and ease of crimping.
1. Cut the factory harness before camera plug, add male deustch 4-pin connector to harness (there’s only actually 3 wires, pink white black, so 3 pin also ok). Wrap with electric tape or shrinking wire wrap (Corsa Technica 1/2in worked great for me)
2. Add female deustch connector to the tiny pigtail with the camera plug. Heat shrink tubing and shrinking wire wrap. 1/2 beer break.
3. Add female deustch to 4-wire cable, I used 20 ft 4x16 gauge stranded molded inside another rubber layer to make a single cable.
4. Snake cable along hatch factory wiring, poke through the left grommet and enter hatch. 1/2 beer break.
5. Go right at hatch and snake into the metal behind the rear motorized hatch arm.
6. Drop the cable with some wire wrap through existing grommet in floor of trunk. Just keep pushing it through, you will see it around the AHC reservoir once you’ve pushed about 2-3ft through. 1/2 beer and maybe bandaid for any sheet metal cuts you have endured along the way so far.
7. From there you can snake it to your bumper / hitch mount receiver.
8. Put a male end on the this cable once at camera location, connect the little “conversion” cable you made in step.
9. Put in reverse and test. Finish beer, do not drive.
I didn’t want to go RJ-45 as I have not had good experiences with frequently bending cat cable and keeping the thin strands from internally breaking. Granted that was 10 years ago and probably older cable tech, but still once bit twice shy.