The wild card would be if the ottomans threaten British interests like the suez or Egypt ..
This could also be a reason to join the fight.
Also if the ottomans wanted to restore Balkan dominance this could be a devisiv split in the central powers.
I don't think the Ottomans were strong enough to do any of that in 1914. Certainly, they needed the CP's more than the other way around, so needless antagonism in the Balkans is right out, especially since only the Bosnians or Albanians might not rebel against them if they reimposed their authority. More generally, they didn't go on the offensive much in WWI, but if they could, I think Kuwait would be their first target instead. Still, probably not unless Britain was already at war with them.
In the event of peace deals I could see Russia loosing gains in Eastern Europe but Petrograd would be off limits and would unite the Russians to fight. They could loose Poland.. Finland .. Some of Belarus .. Maybe parts of Ukraine .. But Petrograd?! No... And I don't think any western power would want that to either. Even th Turks didn't have to give up Constantinople, or the Germans Berlin .. St Petersburg was the Capitol of Tsarist Russia, it's not being given away, Peter the great built that city.
Peace would have to be with in reason, even Brest-litvosk wasn't that insane
Agreed, probably something less severe than Brest-Litovsk, since that was the result of very particular circumstances involving Trotsky making several terrible mistakes at once that compounded each other. They might only lose Poland and some of the Caucasus, or some such.