One of the finest leaders in Westeros was introduced far too late in the game, but that didn't stop her from becoming an instant fan favorite. Will Lyanna Mormont be in Game of Thrones Season 7, and what will she be up to if so? Expect to see more of this Northern leader, who is possibly the only young preteen on the HBO series to hold power with grace.
The Lady of Bear Island is in at least one episode, if the Season 7 photo above tells us anything. With that settled, I have a related question — will she reunite with with Jorah Mormont, or meet for the first time? It's unclear whether or not they knew each other before Jorah was exiled.
The two of them are cousins, and if he had not been sent away, Jorah would have been the heir to Bear Island and ruling in her place. Now that Daenerys has banished her doting adviser as well, it's possible that he could try to go home. Maybe he'll try to take Lyanna's seat back, claiming that it is rightfully his. Maybe he'll try to rally the North to the Targaryen cause. Maybe he just wants a nice place to rest out his days. To be honest, Jorah's greyscale may prevent him from reaching Winterfell or Bear Island at all.
I actually think that, if the endgame of Thrones is a Stark/Targaryen alliance (political and/or romantic), these two Mormonts are a valuable resource. Jorah and Lyanna are both extraordinarily loyal to their chosen monarch. Lyanna pledged to Robb before Jon — she's very serious about the King in the North. If the cousins come together, others may as well. If they oppose one another, the conflict might become bigger than a House Mormont family feud.
Though it is a minor reunion, it is one that I would be very much interested to see. I'd also be fascinated to meet Jorah's estranged wife, who totally exists, but that's another story. At the very least, Jon Snow and Sansa Stark have little Lyanna on their side. Not only is she a sound ruler, but she and her people have proven to be excellent allies.