From what I've read on the numerous RAM sites, adding a brake controller is very easy as the connector is under the dash. As a matter of fact there is a known issue with some of the '16's that the IBC is not sending enough voltage to the trailer to effectively engage the trailer brakes. No fix yet so some have resorted to adding their own aftermarket controller.
As far as the tailgate camera, one can buy the OE camera and harness for around $300. There is a good YouTube video showing how to connect it all up. But you'll need a dealer visit to have the camera activated. I think I read also on the third brake light camera that you need to add an additional harnes for the camera.