The Ottomans as far as I know had stated they will return you the city peacefully as they were asked by the international society. If you choose to capture it (by the way you foolishly did this to Miami too, damaging it) only to look as a hero, thats all your fault.
Texcoco was captured by the Ottomans and you wanted only it to be returned, but now you increase your demands. Who will negotiate with you seriously with such attitude?
And what a pointless question you ask here - "Why so many units who are fighting alongside the Ottomans are Russian of origin?"
As the best cavalry in the world is the Russian cavalry, called Cossacks, and as Russia have many friends, willing to pay to have suck instruments of war, it is not surprising that the Ottomans have Russian Cossacks in their army. By the way, the very same Russian trained Cossacks were standing in your defense ready to shed their blood under the Inca command. While still on the topic, maybe you will explain how it happens that your illiterate sailors sail ships your illiterate shipwrights cant produce? And how your archers will be trained and armed by the Inca with Machine Guns?
And yet, you did not said anything about your false peace-loving nature with all this wannabe-warmongering and the evidence which you denied to even exist?