ah, I actually made a few more edits after I uploaded that and I forgot to change it, my bad.
I got rid of the really dark blue outline on the jeans; its important to have a decent amount of contrast, and to convey depth, but that was a little much.
its a step in the right direction, yeah, but its still really messy and kind of unfocused.
the pants especially have really dirty shading. this is partially an issue of palette. the palette is very improperly contrasted and often the shifts from a dark color to a lighter color are too radical, and in these places the dirty shading is highlighted. don't use such a dark reddish purple for the pants outline peices (and don't inconsistently outline like that, if you're to break an outline make sure its consistent with the depth/shape trying to be conveyed).
are you familiar with hue-shift at all? its a shading principal which states that colors that are "darker" will be natural tinted towards "colder" shades, like blues and greens and in some cases. these shades also tend to be less saturated. similarly, shades that are "lighter" are usually bound to be warmer, more tinted towards yellows, oranges and reds.
there are, naturally, exceptions towards this but more often than not those involve funky light-sources or textures.
anyway - I digress; as I was about to say, its not usually the best idea to have an outline shade be such a saturated shade of dark reddish purple, especially if the object in question is gray-tinted. I'd go for a blueish or greenish gray to help balance it out. I used a greenish shade here so that I could reuse the shade I added in the jacket.
don't be afraid to reuse colors in other areas - value is more important than hue when it comes to shading or creating the illusion of depth and lightsource, which is the primary focus of shading.
speaking of values (that is, how bright or how dark the shade is), some of your values are kind of off. the jacket, especially, has some awkwardly bright spots and some inconsistent shading on the sleeve.
i'd also recommend, although i might be tooting my horn, altering the shape of his hand to more fit the one that I had. his right hand, that is, my edit of his left hand is miserable. i'd also recommend contrasting the skin a little bit, especially the hands; they just kind of blend together into an orange blob.
would you mind if i did an edit of the two other guys?