I would suggest you to really abandon armor on her, since she is obviously not a brute fighter (or is she). I would assume she would use her magic, charms, seduction (since she is a succubus). You should probably think more about her clothes and character, by showing it through her poses, facial expressions, clothes (again), etc.
Since you got basic idea of her design nailed, I would say that those thumbnails fit only for further designing of her overall appearance, but not her character (which I consider to be just as important).
But I really like it so far!
Keep it up!