This didn't end up being the look I was really going for on these (I wanted everything to look a bit more chunky, so 3"x3" was probably way too big for what I wanted). I still like most of these though!

Aside from the main character outlines, everything's done in ballpoint pen on four sheets of paper, scanned, and composited in Photoshop. Keeping track of this many images at once in terms of setting up the different palettes was a challenge too. One-at-a-time is the way to go!