*Bran Stark

He is leaving the land beyond the walls as they have become too unsafe.Also half the people he went in with are now dead. Bran will show us some flashbacks of Rhaegar and Lyanna. I think there will be flashbacks of the Ancient War between the walkers and Night Watch and the Children of the forest. May be he will get glimpses of the Prince that Promised.

*Sansa Stark

Sansa will be left in charge of Winterfell when Jon goes to Nights watch to defend the Walkers. She is not going to be a big shot in S7. There will be some scenes with the Little Finger and that all.

*Arya Stark