Currently researching and writing a book on the Ottomans in WW1.
Here's what I think these pieces of concept art show about the Mid East War
Most likely the Ottoman Hejaz Railway from Damascus to Medina being attacked by Lawrence of Arabia's Arab Revolt troops
This concept art is the first image we have of an actual Ottoman soldier in this game with an actual Bashlik helmet. In the past footage and concept art most Ottoman soldiers in this game were depicted as wearing the German Stahlhelm (which were very few) or just Arab Headdress (of which Arab Ottoman soldiers were hard to come by due to the Arab Revolt.)
I hope this is a sign that DICE will not just reskin German soldiers with masks as Ottomans, as I feared from the first trailer.
Here is an Ottoman Bashlik Helmet for reference
Next is this image which I'm presuming to be the battle for the Suez Canal. This was a major battle, which the Ottomans and Germans planned to take the Canal and cut Britain from her colonies in India. The failed attack was a turning point in the Mid East War, really hope its in the game.
Here is a British armored car with machine gun in the desert. Important here is the appearance of German planes in the desert. The Ottomans had very few pilots and aircraft and employed many German aviators in their ranks, however the Ottoman Air force did participate in several battles. While there were many German planes in service for the Ottomans, they did have their own planes. I would hope and like DICE to get away from only casting it as Germans vs the world, and give other countries in WW1 a noticeable presence.
An Ottoman Air Force plane for reference compared to the standard German airplane with Iron Cross we've seen for a long time in WW2 games.
Lasly, this piece of concept art I think shows the entrance to a Middle Eastern city. I think it could either be Damascus, Baghdad, Basra, Kut el Amara, or even Jerusalem. I'd hope it would be the Battle of Kut el Amara, as it was the major turning point of the Mesopotamian Campaign.