Right but why would that make him support Cersi?

There was quite a bit in this episode that could help set up Jaime as the Queen Slayer.

I think it could be that the Hound dies and turns into a white walker and they end up taking him back to Kings Landing. KL knows what the Hound looks like, so out of everyone, the Hound being shown as a WW would be convincing. Plus, when the Hound came back a season ago, the Brotherhood says that he has a purpose yet. And, just maybe, the undead Hound could fight the undead Mountain.

Rhaegar annulled his wedding to Elia, which should make Jon (or Jaeherys) the true claimant to the throne but Sam got bent out of shape and didn't catch that from Gilly's reading.

Cersei is pregnant. Hooray. Guess they had to have some driving reason why she gave a shit about ruling beyond wanting to **** anyone who had spited her up.

Not exactly support Cersi but make sure the sides are more even so a third option could make itself available and perhaps rally the remains of the rest of the kingdoms to their side aka The King in the North.

Good thought. Or perhaps poor Jorah as that would be really interesting to see Dany's reaction to that.

King Jaeherys Targaryen.

Dany said something about not being able to turn her attention to the white walkers because Cercei would fill the vacuum in the south (unless they can get a cease fire with her).

That seems too complicated. If he wants Jon as king he would do more to support him and Dany getting together or just releasing information about Jon being a true Targaryan and the true king since he should know that or at least have a thought about it which would lead him to investigate it further.

Also, it means that it's actually Viserys and Danaerys Waters...

The problem with this logic is that well, Dany holds no territory in the south except for Dragonstone.

Dorne: Complete chaos probably as lords vie for control.
The Reach: Complete chaos now that the Tarlys and Tyrells are dead.
Stormlands: No one knows since Stannis is dead. Probably complete chaos as lords vie for control.
Westerlands: Still under Lannister control.

The North is a lot more suitable since The North and Vale are allied and friendly toward her. The Riverlands are under Lannister occupation but who knows how long that will last after they lost some of their army in the loot train attack.

I think Danny is clearly falling for Jon. It'll be interesting to see how that plays out when they find out who he really is. Or with Littlefinger plotting to take the North from Jon.

He probably doesn't know. The Kingsguard that were there are all dead and everybody else except for Howland Reed. I doubt Varys reach reaches into the very reclusive Neck and crannogmen.

And the rightful heir to the seven kingdoms. And the Dragons recognize him as Tarragon.

Depends on how annulment in Westros works I guess. Obviously, the marriage was consummated so.....