Ondolemar is now available as a follower with accompanying stat and AI data adjustments. Also included are an appearance only option and an Extra Perks follower option.
Can you get rid of the forsworn?
If the Dragonborn sided with the Forsworn during the quest “No One Escapes Cidhna Mine,” the Forsworn in Druadach Redoubt will be friendly. The Forsworn Briarheart can then be killed (considered the “leader” despite Madanach’s presence) in front of the others and they will not attack.
Can you help the Thalmor?
No, it’s not possible. The bigger thing I’d worry about is that the Thalmor have a habit of winding up on everyone’s bad side. The Thalmor have an embassy and a keep up north, a few agents scattered about (some giving minor quests), and some in the countryside that will attack you if messed with or even on sight.