Giving up Riften pleases the Imperials, giving up Dawnstar pleases the Stormcloaks. Phase 3: You must give up either Riften or Dawnstar to the Imperials.
This turns the favor toward the Stormcloaks side, which then triggers followup options to give something to the Imperials. This seems unavoidable, as there is never a dialog presented. Kicking her out pleases the Stormcloaks, letting her stay pleases the Imperials. Here's what I've got based on the available choices/branches: So I found that whole bit rather interesting, and wanted to break down all the possibilities.
