Drinnor
Send him to the wall and put punitive punishments that applies only to the Starks land and the Tully lands that they rule directly. There is many ways of punishing a vessel that doesn’t require the death of the family member. You need to reduce the Starks in the eyes of the north. the Starks need to be punished and need to be something that is known and felt. One of the ways of dealing with this is inviting northern lords that liked Lyanna to private meeting. show them the evidence of what Ned and catlyn has done. I would have the evidence presented in the most negative light possible. doing the best to make Ned look worse. Put into their head that royal family respect them and is asking for their advice and what they would do if this had happened to them. Reminding them of the love between Rhaegar and Lyanna. This is a good way of eroding some of the northern alliance and unity. Rob would not be able to call his banners if many of the lords believe that house stark is the guilty party.