Yes, I agree.
Ethel certainly has frizzier hair , worn short in both the other photos.
Eva in the bottom photo has softer longer hair, and that goes with the front girl in the top one who has her hair up. As the top one was probably taken a little later, Eva would have been a little older and thus started putting her hair up. Showing the squarer hairline that is also apparent in the bottom photo.
Hair length or style would normally not be a sensible strategy to use, as it can change so easily and frequently , but there does possibly seem to be a pattern here?