If you want to change the final chapter: do you have "the witchwar legacy"? You could use that one as well.
Since one of my players wanted to play a rebel/revolutionary, I adapted her background story in order to make her character one of the Heralds. My group will be starting on The shackled hut this weekend. They are mostly very experienced players and heavily into roleplaying. My problem is a luxury problem, namely that they always take too many NPCs along. They attacked the Pale Tower with Nadya and her 4 warriors, Emil Goltiaeva (long story; they more or less set up Emil and Katrina against each other), Iziamir the blacksmith, Hatch and several Pale Tower guards, one of which was charmed. The others were more or less converted to the revolution (after consuming lots of alcoholic beverages and having to listen to a long political speech, made by the rebel character, accompanied by a successful diplomacy check).