Iran wasn't officially a belligerent in the war, so a formal annexation of Iranian Azerbaijan by the Ottomans is very unlikely. On the other hand some form of Ottoman influence in the region is possible, but the Russian Revolution and Civil War would certainly complicate matters in northern Iran.
It's not too hard to have Afghanistan and Iran involved in the war officially. If the Gendarmine get to the Shah before the British. If the Central Powers are winning both nations are likely to consider throwing their hat in before peace is concluded.