I think you are right. They could be head swapped with Esci/Waterloo Arabs or Hat Turks to give more variations. They could be used against the WWI Cossacks as well as Mespot and Palestine. The Bengal Lancers would probably be OK for WWI also to face them . The 9th Bengal Lancers for example were in Palestine.
I hope these WWI sets include a few dismounted figures like the Hat proposed Australian Light Horse.