You've got a good grasp of anatomy! My recommendation would be to try a more primal look/feel, perhaps some more exaggerated facial features and hands/feet. Show us how deadly or vicious this creature is.
While you want to go for a humanoid beast, it would still be cool to see how those animal traits could pop up in your creature. Keep it up!
Edit: I looked back at your initial sketches and I quite like 4, I think that one is pretty awesome and you should definitely explore it!