Before I read your entire post, I was going to suggest checking the connector at the BCM. Sounds like you got it solved. Newish vehicles really begin to act crazy when resistance is encountered at the electronics connections.
My sister has a 2012 Dodge Caravan that would operate the wipers, turn on the headlights, blank out the dash, sound all the chimes, etc. and so on totally at random. I googled it and found that LOTS of people have the same problem. Many spent thousands of $$ at the stealer to have it fixed (replacing wiring harnesses, modules, dashboards, etc.), with mixed success. It turned out to be a loose BCM connection in the passenger side foot well. Someone along the assembly line forgot to push down the clamp on the connector. If I had to guess, I'd say it was a training or M&P issue at Dodge. Based on my research, I'd bet there are hundreds or thousands of vans with this defect.
Anyhow, I'm glad you got it fixed. Anytime a vehicle acts like it's possessed by a demon you can usually trace it to a rogue connection at some module. The dealers like to guess and replace stuff at your expense.