Maybe Sansa was playing Littlefinger, or she realized siding with Arya was the smarter choice. To me it said despite learning how to be treacherous she was still a Stark. Starks put justice, and integrity above all. (Even their lives) I don't see much changing once Jon finds out he's a Targaryen. Incest is kind of their thing. What makes him a hero is that he never wanted to be a King, and even if it doesn't pan out with Danyeris, he's just fine with staying in the North. That, or they marry anyway, unite the 7 kingdoms, then produce a batshit crazy inbred Targaryen that starts the vicious cycle all over again in the future.
Was that fire, or what spewing out of the Ice Dragon? Some kind of undead fire Maybe? It seems dragonfire, living, or dead, trumps all magic in the world.
I think we're going to see a twist where Cersi dies giving birth, and Jaime dies in a moment of redemption, living Tyrion to raise the kid. Redeeming his actions which inadvertently killed his last neice, and nephew. (Something that didn't dawn on me until they pointed it out.) Perhaps Jaime convinces his remaining loyal forces to follow him into battle against the Others. So Sansa sends Arya to secretly finish Cersi only getting there in time to see her die in childbirth. That leads her to bring to the kid to Jaime (who's dead by then) thus giving the child to Tyrion. The Hound goes with her to take care of the mountain. Arya marries the Baratheon bastard, whos granted legitimacy, and restrengthens the bounds between houses. At this point Sansa's done with men. Maybe she enters a civil union with Yara. (Whos gonna get rescued dammit!) Only because everybody thought Arya would be the lesbian. Bronn breaks that Martell chick out of the dungeon, for a price. They live happily ever after.
The dotharaki go home, and become the cops of Essos. From invaders to peacekeepers. The unsullied marry the widows of war (winning them over with their warrior cunniligus skills) and make new unsullied warriors out of their stepkids. It might happen. Obviously they can't breed.
I think we'll see a undead Tormund, and Hodor among the dead army.