FWIW, I was able to locate a 2016 E series dually axle (dana 80) - think it was from an RV and it fit perfectly on my 2010 E350 - no changes to shocks/springs or drive shaft, pretty much bolt-in. Even came with factory mount for the rear sway I added.
Mine came with 8x6.5" standard Eseries bolt pattern and dually wheels which was a bonus so I don't have different lug patterns and can carry a single spare. My sensor is not on the axle so no issues there either and even had the same rear brake line drop as my E350 (which I've replaced).
Finding dually fenders for an Eseries is only the real hangup, not able to find a reliable source anywhere.