I like to entertain theory's like:
Wanda = Lemore
HR knows the Elder Brother
GNC: Manderly knows for fact that Bolton's Arya is a fake. Arya's been to White Harbor with Ned, 2X
Robb's Will names Jon.
Northern Clans checking Jon out: Jon sending Stannis to ask for their help.
Unknown to Jon = leader of the Wildlings: Took their valuables before they could go through the Wall.
Possibility that I haven't trashed: HR=HS
Marwyn was Maester for Lyanna's birth
Summerhall was murder and not an accident gone bad.
So yeah, I'm reading between the story lines. It makes the years between books more interesting.
At least Manderly knows that the Arya the Boltons have is a fake.
In AFfC while in the HoBW Arya remembers going to White Harbor.
"She had visited White Harbor with her father twice, but she knew King's Landing better."
Going with Ned, Manderly would certainly have honored her as family member accompanying his Liege Lord.
It's interesting that Rhaegar, Jared and Symond Frey disappeared just after they left White Harbor and couldn't tell about any ships they may have seen during their stay. At this time it appears that nobody outside Manderly's control knows about the 23 ships in the harbor and the other 20 or so upstream on the White Knife and those that may have found out have disappeared (Frey's and Davos). Manderly knows that Ramsey's Arya is fake as the real Arya went to White Harbor twice with Ned (Arya II AFfC). The fact that Wylis has been released from captivity and is back in White Harbor (Manderly's heir) and that he and Robett Glover are in on Manderly's plans and not with the wedding party inspires the possibility for some action.
In GoT, Arya 1, when Arya leaves the sewing circle to watch the boys practice swords, she and Nymeria encounter Jon and Ghost at the window.
Nymeria stalked closer on wary feet. Ghost, already larger than his litter mates, smelled her, gave her ear a careful nip, and settled back down." Later, in the same chapter: "He messed up her hair again and walked away from her, Ghost moving silently beside him. Nymeria started to follow too, then stopped and came back when she saw that Arya was not coming."
It looks like at this stage, Ghost has already taken on the demeaner of Jon in interacting with Nymeria in a similar way to Jon's interactions with Arya. It also shows that Nymeria has an instinct is to follow Ghost/Jon, but loyalty/love to Arya overrides the instinct.
When you ask "Which Direwolf is most powerful," to me it's the one that commands the respect of the others. Clearly by this interaction, Ghost has Nymeria's respect.
On the way to Kings Landing to be Robert's "Hand", in the Barrowlands, Ned informs Robert how Kings Landing was taken after the battle at the Trident. Until then, Robert thought that it was his men that had taken KL. It wasn’t until this exchange that Robert became aware that it was Lannister troops that took the city.
I thought that it was common knowledge that it was Lannister troops that took KL. It seems as if everyone knew that The Mountain took Aegon and bashed his head against a wall and raped Elia before mutilating her. So, why wasn’t Robert aware that Lannister troops had taken Kings Landing prior to Ned and the rest of Robert’s army coming to it? To me, this confirms that Ned didn’t go to Kings Landing when he was returning from the Tower of Joy. Why was it so important for Ned to bypass Kings Landing where his best friend who he grew up with would be crowned King. Where he, being the primary commander under Robert and Jon Arryn would be given great honor, and where they could both grieve the loss of Lyanna. Instead, Ned takes a newborn child to Winterfell far from anyone of note.
Here's a "What If" crackpot theory. Suppose Aegon V had seen the type of guy his grandson Aerys was. Perhaps Aerys reminded him of someone (Aerion) and knowing how frail his son Jaehaerys was, he had second thoughts on his decision to disinherit Duncan. This would have infuriated Aerys. A young Pycelle was newly sent from the Citadel to Aegon's court. Perhaps the Citadel would be patient for a decade of Aegon's rule but in the meantime Pycelle would be there counseling and steering the guy they want in Aerys. Having Duncan become King after Aegon would screw up their plans. Pycelle could have arranged the whole Summerhall event. This was the celebration of the birth of Aegon's grandchild at their summer vacation home. Everyone would feel safe and secure, Guards and sentry's would be minimal compared to the Red Keep. Pycelle knows how to handle wildfire and distributes it in advance while arranging the birth celebration. By killing the King and the King's heir, Aeys is guaranteed to become King and through Pycelle, the Citadel gets who they want to sit on the Iron Throne.
This scenario seems more realistic than trying to hatch a dragon that hadn't been hatched for a hundred years