Originally Posted by Simon
A neutral Britain and the Ottoman Empire is the hard one that's going to require several changes from our timeline. First you have to get the Ottomans away from the Germans and with the British and then have the British stay out active involvement in WW1 but still provides favourable aid for the Allies.
Neither Britain nor the Ottoman empire were obliged by treaty to join in WW1. They did so as much because of internal politics as outside events.
In the case of the Ottomans a different relation with the Germans would be required, say military advisers, etc by a different European power. The trouble here is that of the other Great Powers, Russia sees itself as protector of the Orthodox subjects in the Empire, French the Catholic subjects and Britain is holding Egypt. Of the other powers the Austro Hungarian empire is a bad history with the Ottomans and none of the others have cash like the Germans.
What would keep the Ottomans out the war is not a more stable situation but a more unstable one, say a full scale Arab revolt. Under those circumstances Istanbul is going less interested in a war in the Caucasus Mountains than trying to string up ibn Saud and his fellow rebels by certain piece of their anatomy. Moreover, given that Britain can "support" Russia by supplying arms to the Arabs and so keep the Ottomans out of the main war they would probably be more than happy to do so.