I ended up figuring out how to eject the pins. I think drilling the hole in the hatch would have been the better option; much less chance of a mistake. And the grommet the harness ships with is pretty stout....it would never leak.
Here's how you do it. The pins are held in underneath by plastic...
I am stumped on the step involving removing the wires from the backup camera wiring harness. I have removed the very front piece of the wiring harness, and I have flipped up the plastic locking mechanism. What step am I missing?