Maybe a shift in the instructing model is needed? Often firearms instruction is a situation of a single teacher or maybe several, but they are "THE" instructor. Maybe a bit more of a team atmosphere could be promoted to instill a sense of trust and broaden the possibilities for learning. It's amazing what things can be learned by students, from students, especially when the students aren't all of one skill level.
I really think some insight from coaches of female sports might be the best resource you could interview. They have been at this coaching thing for a long time and deal with all female classes or practices regularly. They probably have some great insight for this.
I learn new twists on grappling techniques from fellow students all the time. It's often a slight change to a grip or a change in angle that make a technique or move more efficient for me, because of my size, strength, flexability or whatever. If your is all female and the get to a comfortable team feel, maybe it helps to broaden their learning.
Just some random musings on some possible improvements that could be made to the earning experience. Even if they aren't entirely on topic.