I personally really like the blue on #2. It adds a splash of color in an otherwise graybrown setting, so to speak. Also about him, did you intend to color his shoes? As for #4, great improvement over the previous gender confusion. The tomboy image is captured pretty well. My only question is about the gold thing around her waist. I saw the black part as being a hoodie that got tied around her waist at first, but then when you see the hood around her neck and the golden plate like object, it doesnt really make sense. I might just not understand exactly what that entire thing around her waist is, and if it's something totally different than my interperetation it wouldn't surprise me. The only other little nitpicky issue I see is #2's left arm. You can see that it's there, you can see the arm's angle, but the hand looks a little strange and unoccupied. Maybe if you angled his arm a bit more to his center of vision it might help.