The Westerlings seem to have had some kind of understanding with Tywin Lannister, the mother refers to this after Riverrun falls. It's probably too conspirational to suppose they intentionally tried to marry Robb so Tywin could wean the Freys away from the Starks and have them kill them all, but I do wonder what's up with that.
Reliant Robin wrote:
I think Dany, as the surviving legitimate Targaryen, could legitimise him if she wanted, assuming some distant future where they meet, recognise each other and want to.
That's a lot
of ifs. Who would actually know that Jon Snow was Rheagar's son? He looks every bit a Stark, so it won't quite be 'egad, you're plainly a Baratheon' like Gendry.
No, if there's anyone who can identify Jon as Rhaegar's son, it would be someone who knew he had a son by Lyanna... and sort of a seance, that isn't gonna be Ned Sterk.
As far as Daenerys goes, Barristan the Bold may know precisely this.
In fact, isn't the last time Barristan saw Daenerys the time he revealed to her all he knew about the Targaryens? If
he knew, then he may have already told Daenerys about Jon. There's food for thought, or not.
Beyond Barristan, it would not surprise me if Varys knew.
Out Of My Vulcan Mind wrote:
Robb made someone his heir and put it in writing, but it wasn't revealed who he ended up naming.
Robb explicitly made Jon Snow his heir, actually, though over his mother's objections. I don't remember offhand if any witnesses to this besides Catelyn even survived, though. There were
other possible candidates, which she referred to briefly, but they were basically like descendants of some great grand uncle of Ned's, the sort of family many times removed who normally wouldn't be taking over.
Lord Commander of the Night Watch, King of the North, King of the Seven Kingdoms.. christ, we may as well make him Azor Ahai at this rate.