You have some really neat ideas, and those anatomy studies are coming along great too.
I'll echo what Lulie said about faces. I'd like to see you do some studies of emotions, because a lot of your characters have a very neutral expression on them.
By the way I like the succubus in the spiderweb. It has a very nice sense of weight to it, though perhaps the succubus is looking too relaxed given how tense all her muscles would be in that pose.