Jon has the strongest claim if he can PROVE that the marriage took place AND that he’s the resulting child.
Then it becomes a matter of who is willing to back him.
If he marries Daenerys to create peace and takes the throne with her, then it is a union of ice and fire.
What would be interesting is if they make Sansa and Tyrion’s children heirs to the throne, since Daenrys cannot have children. The hand of the king has a vested interest in running the realm, Sansa is still the mother of princes and princesses both for the realm and the North. And likely Casterly Rock, too.
Sansa’s and Tyrion’s marriage was never consummated so it was like she was never married.
Children? Are you speaking of children Sansa may have sometime in the future?
Seems like Sansa’s future is tied to Winterfel and Littlefinger highly desires a marriage between them so he would be in a position to be a King but not on the Iron Throne.
So many possibilities...