To anyone that may be experiencing this same issue....
I one morning had the exact symptoms described in the original post. Everything was fine when I parked one night, and in the morning the infotainment screen didn't come on, no radio activity, no bluetooth, no backup camera. My initial thought was the screen, but that didn't explain the lack of other functions. First dealership tried the usual fuses and such (exactly as I had told them I had already done), charged me for half an hour of labor, and said they would need at least another 2 hours to trace wiring and whatnot to try to diagnose it. I didn't like that idea, seemed unlikely to be wiring in my mind, and I picked me car back up.
I tried opening up the dash, disconnecting and reconnecting all the cables, and that got me no where. Finally found this thread that said it was the actual radio unit back there. Since that seemed likely, I found one of only 2 on eBay that matched my exact part number, installed it, and paid the dealership an hour to update/program it, and voila! Everything works again.
TLDR, infotainment screen not on, radio not on, no bluetooth...new (used in my case) radio (with exact same part number as I pulled out of my car, there are many options) fixed my issue after programming at dealership.