Alright, you wanted some comments, and it looks like you could use some. I mean, no one posted here, what's up with that? .-.
Anyway, overall, all your pictures don't having shading. Scrafty and Scraggy do show some shading, making it look less 2-D, but it still needs more shading. They both have a feature that looks like pants. What you could do is shade it like clothing. Make those lines look more like angles and folds. Study clothing, and look at the clothes. The shading, texture, ect. Or, have a reference.
Clean off those white pixels from your outlines! They don't look good! Do you color on the same layer that the outline is on? o..o If you do, DON'T! Make a layer under and then color. It make a difference when coloring. c: Also, make your outlines look cleaner, and less bumpy looking. Try to keep your hand steady and draw the outline. Drawing slowly, and with your hand moving a lot will make the outline look bumpy. ;o
As for background, I wouldn't paste your work on a background you didn't make. Try to make your background instead! =]
I would check out some tutorials on dA to help you with your outlining, shading, ect. =o But still, nice work. =]