Thank you to everyone who has posted in this thread, it was very helpful reading through to see what worked and didn't. In the end, I was able to find what I hoped was the right set-up for my truck.
Went ahead and tackled this today and it was relatively smooth, no issues and it is ready to go! For reference, here is what I used for parts and the Alfa settings.
Bought used taillight assemblies that were for parts and didn't work according to the listing. They had what I needed though, sensors and the heatsinks. I did order the internal harness for the sensors from Jimmy when I got the 360 surround and passive entry wiring. These taillights had the wiring all intact and looked good, so I'll be selling the extra harnesses.
LH - 68263397AC
RH - 68263397AD
When I did the 360 Surround, I bought new mirrors that also had the BSM glass
De-pinned terminal #8 from the LH 300AA jumper harness. Heat shrinked it and taped it up to the harness
Pinned the xy400, this was easier than I though it would be
AlfaOBD settings:
Cabin Net: BSS Blind-Spot Sensor/LBSS Left Blind-Spot Sensor (did not have the Cabin Net-LBSM Left Blind Spot Module setting)
Cabin Net-RBSM Right Blind Spot Module – Enable
CustSetMenu 1-Blind Spot Alert CSM – Yes
Car Configuration Change: Doors-Blindspot Mirror Present – Yes
Cust.Set.Menu 3: Trailer Length Blind Spot Enable/Disable CSM Present
Everything shows up on the UC5 screen and the lights go through the initial self-test. I'll have to go take a drive and test it tomorrow.
Next mod, aux switches....