I just got the peaceful resolution for Revaire and I can confirm that you *don't* need to be friends with Gisette, like, at all. You just need to pick enough of the right arguments (and have the stats?) to convince her to work with you.
Definitely not that, I can "greatly influence" 2 options, but the one that encourages peace in general just increases conflict, for example, I have three options in that last choice for Revaire, Increase Peace (which only increases conflict ), Increase Allies who are for Peace, and Argue for better negotiations for Revaire.
By the way, I sorry for the nitpicks, this is a marvelous game that I love and have been looking forward for years. It is every bit as good as I ever imagined! Thank you for it!