The Ottoman Caliphate and Greece will agree to peace with the Balkan League, with Non-Aggression pacts in place for a minimum of three years.
All Ottoman Balkan territory outside its OTL borders will be split between the Balkan League countries and Greece. (Within reason. The countries receiving the land must have some legitimate claim to it and must be able to defend it.)
Greece will issue reparations to all other combatants for having to be added to the peace terms for doing absolutely nothing in the first place.
Muslims and Turks in former Ottoman Balkan territory, as well as in Muslim-majority areas of non-Ottoman Balkan lands, will be offered the choice to go to one of the Islamic nations. Whether they go and where they go will be up to them (read: will be determined by RNG).
Russia will remove its blockade of the Ottoman Empire and will refrain from reinstating it for a minimum of three years.
Any of the (hopefully former) belligerents who does not agree with these terms will continue fighting the countries that they had been previously fighting.
For the next five years, materials will be sent to Montenegro to jumpstart their under industrialized economy.
Soldiers and spys are sent to Serbia to help fight against rebel groups such as the Black Hand, Young Bosnia, and Narodna Odbrana.
Princess Helen and Prince Alexander are sent to Bulgaria as wards of Tsar Ferdinand I, as well as the ironclads Vasilissa Olga and Vasilefs Georgios.