I'm not expecting any characters to get 'comeuppances' or 'happy endings' in DoA. The feeling of the strip is wrong for that. It is more a 'slice of life' strip, as far as I've been able to determine. What Willis is trying to do is tell the story of the first year in college for these characters and outline the influences that informed their development from children to adults.
For Joyce, it looks like it is going to be a crisis of faith. For Amber, it is going to be having to confront her mental illness and accept that she can't stuff it into a fantasy life. For Ethan it is not running away from his sexuality. For Sal it is likely going to be having to admit to herself that she can't isolate herself and be this self-reliant mystery if she wants to be happy. However, I don't think that we're going to see any 'ends' (after all, it's only going to be Freshman Year). I can see a follow up 'DoA Adult Life' strip that may refer to their later experiences but I don't think we'll get any massive narrative conclusions from them; that doesn't happen to real people in most cases, so it isn't really likely to happen to these characters.
With regard to Mary, I can see her continuing to be an increasingly disruptive influence in the dorm and, eventually, her parents transferring her elsewhere because the increasing level of isolation and opposition she's facing is impacting on her education (and it's an easy way to define her move as the act of a victim rather than a defeated aggressor).