More than likely get called off anyway I think, look at it this way would GNE really want to lose out on 3 days travel takings, which I assume would be quite a substantial amount of money for that small period.
As for who will operate the services if does go ahead I haven't a clue, I can see Nexus although some may say it nothing to do with them, stepping in and sorting it all out.
I would think Independent companies like Weardale would operate a few services if need be like what they do for Arriva on Boxing Day. I can also see Arriva operating some services as GNE operates some of there services on boxing day also, so they could return the favour so to speak.
Just going to have to wait and see what happens.
RE: Go North East