I’d work on the lips of your female faces. They all look like they are stuck out in some odd way. Not quite pursed, but something like that. I think it’s really holding back the feminine beautiful quality they almost have.
And your woman with her head tilted waaaaay back, I think the neck needs some more defined muscles. With a pose like that the skin is stretched super tight and you can see all sorts of muscles and veins and ligaments. Also, her breasts don’t seem to be hanging correctly, but it’s hard to tell which way is really down with the piece so I might be wrong.
But overall this is cool stuff!