Update: still don't have the brake lights working, but with a trailer attached, and going into reverse, it does disable the PDC and defaults to the 'top down' video mode. I hadn't been able to play with it much, and don't know if any other video modes are available. So, without programming the vehicle, the Right-Connections harness does enable all of the 'normal' trailer functionality as the OEM version, and once I get the brake light glitch worked out, I'll be all set.
What slowed me down during this troubleshooting was the stupid cycle light bar I bought...with a nice QC sticker on it, I assumed someone had actually tested it! Well, if they had, they'd have found that it wouldn't work! The leads to both the brake bulbs were so loose, they had fallen off in shipping. THen, in the trailer plug, they'd tightened down the screw onto the insulation, not the wire. So, even after repairing that and checking the trailer harness fuses, the brake functions still didn't work. I've sent an email, and hope to get some troubleshooting tips.