Not really. I could see a couple of candidates.If the showrunners are really going to honor GRRMs ending then Jon HAS to be the one to kill Dany. Nothing else would make sense and I would be terribly disappointed in finale that didnt end that way.
You talk about Forshadowing.
Jon who loved Ygritte and had to watch her die after being unable to kill her himself
Jon who got killed himself by his own men when they thought he was going to betray them.
Jon who has turned down every overture to lead but put it all aside for his love for Dany.
No Happy Endings
He's got to do it. He's got to kill her and ride off with Drogon into the sea or essos or become a wild ling.
No Happy Endings
We got aryes. We got the king slayers blood line still in go.