There currently is one option to travel by night train from Bischofshofen (Austria) to Münster (Germany), taking approximately 14 hours: Namely the UEX 1310 operated by UEX.
UEX (Urlaubs-Express) runs seasonal night trains and car-carrying trains between Germany and Austria.
You can choose a seat, a couchette berth, a whole couchette compartment, a private sleeper compartment or connected sleeper cabins.
You can bring your car, but only between the car terminals, and you book the vehicle along with your ticket.
There is a free ski compartment. Drinks and snacks are available in the bistro on board.
Children with their own seat or bed pay a reduced fare.