I'm not sure how much I can help with graphics, however, I may have some ideas on how to make this process easier and ultimately more scalable.
Maybe make characters buildable/customizable, e.g. have different heads, clothing, etc. all fitting to some sort of overall template which contains the frames and animation.
This would make it way easier to have a wide variety of characters without having to do too much on the graphics side. Also its easier for a community member to contribute something simple like a hat or clothing style for a character instead of reanimating everything.
Also, if you're dealing with weapons, you could look for pictures of different paintball guns of the web and use those as a basis for the design side. You could even extract the shape of the guns to use as templates much like the characters. These types of "lazy" methods of design are perfect for people like us.
Also, easy customization is a good feature for games with online profiles.