You can see the original headshots of the main cast here and then a full lineup of the cast here.
First up is a color test on that previous lineup. Everything here is still in various states of flux, even in how some of the characters are designed on the whole. So certain characters might look completely different when the comic itself is out! Click to see a larger version!
Next up are a couple of sketches that Caroline did. These are her takes on the four main characters, with a fairly heavy redesign attempt to one of them. It is very possible I might be adapting some of her ideas into the final character designs...