I was thinking about how the First Order came about and its composition going into TFA and it occurred to me that could hint at how Kylo might be redeemed without dying.
In Canon we learn a large number of planets leave the Republic and form the political backbone of the First Order. Even if the the invasion is stopped, it’s unlikely the Resistance will have the forces or will to conquer these worlds. Further, the military resources of the FO are formidable and its forces fanatical. Even if Snoke and the military leadership were killed, it would still take a lot of fighting to stop the war. In fact, it would leave the galaxy in much the same position as it was after RotJ, a leaderless Empire fighting itself and the rebellion turned Republic. This eventually resulted in the FO. How then, to break the cycle of violence?
This is where Kylo comes in. Once Snoke and Hux are gone, Kylo would be the leader of the FO. Instead of going into exile or submitting himself to a non-existent court, he would be in a position to order a stop to the war and maneuver the FO towards demilitarization and peace. It would go far in showing his redemption was serious and prevent a repeat of the end of the OT. He would finish what Vader started and bring peace and order to the galaxy, just not in the way he envisioned.