There is a lot of room to work with that would allow DC to take one of Wonder Woman's few and forgotten arch villain's and reboot her for a natural fit into a WWI era movie. She's an Aristocrat, could turn out to be Hitler's mother if they really really wanted to keep the Nazi connection, and has a history with facial scars and has been depicted wearing an iron mask in the Batman Brave and the Bold cartoon.
Also while WWII documentaries tend to overshadow WWI ones, one of the few history facts the average person does know about WWI and ironically associates with it is the Red Baron thanks to Snoopy's repeated imaginative adventures fighting him. Red Baron....Baroness... There is plenty of room to do something with that, make them the same person, make them related to each other, or link them together in some other way.