Frustrating leak?

I have a leak that's driving me nuts! I tried to narrate through the captions and pictures about what's going on. I'm trying to find the source of the leak and have had no luck thus far.

1st pic: drip point (underside view).

2nd pic: my original theory is that water was coming down (the blue colored area) and somehow getting behind the rubber gasket seal that goes all around the trunk opening. Leaning toward this not being the case. I silicone sealed the area pretty good and still got water leaking from the exact same spot.

3rd pic: my next theory is that water is getting through the wiring harness seal, dropping underneath, running down some kind of channel that leads to the drip point.

4th pic: underside of wiring harness and a visible rust spot, with some additional rusting in the top right corner of the pic.

5th pic: a better picture of the rust from the top corner of picture 4, but curiously doesn't appear to be a leak point.

6th pic: detailed straight on shot of the drip point.