Really excellent job. I think my biggest crit is the dark tones in the diffuse. I think they look a little "dead". I'd try to saturate and color them a bit in the diffuse, or if you have control over the shader, try to do it on that side. The sculpting is superb though, and I love the costume design.
My vote would be #4 but keep #4's collar-- it just looks like it matches the outfit more, whereas 3's collar looks like a dog collar because of the stark contrast between the blue and yellow. I would also opt for a bit smoother looking diffuse on the blue padding-- right now the blue looks a bit too noisy (though I'm…