Hello BKirch,
I am interested to see what your scanners turn up. I have been without reverse lights/camera for ~6mo now and have had the same things happen as you described. No additional audio equipment here and no recent windshield replacement (~18/24 mo ago) so I think you are probably safe there. In my researching I think that the connections from front to back runs from a box behind lower glove box referred to as an HMI box down to the frame on the passenger side, along the frame to the back of the truck, over to a collection of harnesses on driver & bumper side of spare tire, and then splits to lights/trailer harness/camera. My fuses all check out as well and I have unplugged/replugged in each of the harnesses to see if anything changes but no dice. I've wired up some spare pod lights under my bumper and hooked them into the trailer harness to serve as reverse lights until I find a fix. I have read about camera failures where the HMI box needed to be replaced as well as just the camera needed to be replaced but none also lost reverse light functions.