I had actually wondered what it would be like to have all the costume characters sitting there with the helmets/masks in their hands. But I think that would work best as a supplemental photo. Have this one and then a second one with their masks off. If you just have it with masks off, some people would gripe that they want it the other way. So just make both happy.
I wish both Alec Guinness and Peter Cushing were alive for this shoot.