When working with small sprites, every pixel is important, so you've gotta really focus on how much detail you want to put into them, or else risk sacrificing readability.
The Pink Skulleton is a nice balance detail-wise--not too little, and not too much, and I dig the colors. Where is the other arm though?
I think the leg and the wrestler have too much detail; the leg is so defined that it ends up looking like a wooden plank. I think you should use as few shades as possible for it. The wrestler (I assuming the face is unfinished) is pretty good, but it'll be next to impossible to pixel in the chest hair without making it look like a brown blotch on his chest.
On the other hand, the woman doesn't have enough detail to me; I think her dress could use an extra color.
The sheriff--does he have a head??--would be readable, but the pastels throw me off. I think darker colors would suit it better.
They're pretty nice all around though--I hope to see how these turn out!
