It seems unlikely given the time period. Europe is still very big into monarchy and inter-European wars so that level of international cooperation would be out of character. Possibly the London Conference after the Greek War for Independence gets to pick a king for a second new nation. I'd put more money on a revival of the Kingdom of Jerusalem or some kind of agreement with Muhammed Ali Pasha as the post above noted leaving it under defacto Egyptian rule.
Greek immigration to America ? Couls even see a larger community in Orthodox Ethiopia than OTL . OTL there had been a exiled Ottoman Greek community that persisted until the Derg regime in 1975 and ist even there today in very small numbers.
This seems likely whether the Ottomans win or lose the war they're about to start as the populations of Greece and Anatolia are going to try to get out of the way of the war.