Yes, this is the last proper turn. Next week it will be voting time. After that: wait and see!
Ar-Ulric will declare a cease-fire, two weeks of fluff time (not real time!) before Midwinter's day. That allows all the electors to travel to Middenheim - and no, it is not possible to stop other people's electors from voting! Ar-Ulric will excommunicate anyone suspected doing so.