My theory :
Jon is a dead man walking, I think in the end, Jon becomes the night king, (how that happens, not sure, he would have to be stabbed in the heart with dragon glass, and has already been stabbed in the heart before) and goes back North of the wall.
Brann's statement about mostly living in the pass is a reference to nearing the end of the show, and that everything will repeat like a never ending loop.
In a episode in season 7 the meastors in Old town were talking about a prophecy abut Ergon Tyrgairian, and being killed by the drowned god (Iron born statement: the dead will never die/and there king must survive by being drowned) and making a comment about it never happened.
And in the end it doesn't matter who ends up sits on the throne, because winter is coming again.