one "theory" I can up with is dealing with Jon. With Jon being "dead" I think he'll eventually have to take the place of the night king in order to "end" the war, at least for a few thousand years. Ayra will have to kill him, and her dagger and then he will become the night king.
thats my "wild theory"
if it just ends in a "normal" way, then I think Jon will marry Dany, and Sansa will marry Gendry.