Just a note regarding the Great Northern Dome car issue with the dome seating assembly being backwards as when I became aware of the issue, I simply contacted my train store to make them aware and since they still had some cars that were not picked up by customers, they had their service folks look at the cars which of course were incorrect as reported.
Fortunately, their service techs are Lionel certified (from the old Mike Reagan days) and very experienced so as an "interim" fix they simply took the cars apart and rotated the seat assembly and now the seats are in the correct direction.
So is it a "perfect solution "NO" as now you cannot see the staircase as it is blocked by the end of the seat assembly although you have to look really close to see it.
In respect to the "interim" repair it's about a 5 minute fix as you simply remove 4 screws from the bottom of the car, disconnect the lighting harness and the 4 screws holding the dome seat assembly in place, rotate the seat assembly and now it's facing correctly.
So once Lionel comes up with a solution to correct the problem the above would get you by and as John mentioned the set was pretty expensive and it need to be corrected.
I also have a set of the American Orient Express cars on order as it appears the dome car has the same issue and have instructed the train store service folks to take a look at the dome car and if possible, do the same to it until Lionel has come out with a fix.
The solution above is most likely not for everyone just wanted to share what I experienced and decided to do for myself as an interim solution.