Will Sansa betray Jon?
I think the question that needs to be answered here is how important is family to Sansa? I honestly don’t think that she finds Littlefinger’s proposal tempting. I don’t see how she could ever forgive him for what happened with Ramsay. I don’t see them becoming a power couple, I don’t think she could ever trust him considering she also witnessed the scene between her aunt and him. She has even said so herself, “Only a fool would trust Littlefinger.”
I actually adore Petyr’s devious character and am in no hurry to see him killed off, but I support theories that Arya or Sansa will be the one to kill him ultimately. If she does team up with Littlefinger to overthrow Jon, it would be a very brief alliance where she kills him as soon as she gets what she wants.
Sansa is so familiar with being powerless for most of the show, I can see her getting a lot of satisfaction out of ruling. I, however, do not think she would be willing to participate in her family’s murder to accomplish it. With Bran and Arya near there may still be a reunion, and if that reunion took place I think it would drastically decrease her willingness to overthrow Jon.
I more so see Jon going to be with Dany once everyone becomes aware of his parentage. Perhaps he will leave the North in his sister’s capable hands when he leaves.