I had to respond to this thread because someone I consider a dear friend made it.
Zodiacally I'm a Gemini which suits me for most of the roles on this list. I have the heart of a hero, but not the steadfastness. I have the distrust of the 'status quo' of the anti-hero, but not the bitterness. I have the loyalty of the trusty sidekick, but not the lack of initiative. I'm a natural strategist as the wise old mentor, but no 'victories' to my credit. I have the intellect for the comic relief, but not the timing. I have the passion for the love interest but not the charisma or looks. I suppose I could be the smart guy who does the planning - especially for the villain (you know, the guy whose genius is exploited by the one with the vision/deviousness to carry it through), though my heart isn't in it. I've never been the big guy who does the fighting as I'm perfectly average physically, but it doesn't appeal to me anyway as I've always worshipped wisdom rather than brawn. I could be the loner, but I'm very social so it would be strange circumstances that would cast me there. I'm intrigued by the "morally ambiguous wildcard" because of an anime that I was introduced to some 20 years ago called Shinjuku: The Demon City. If you get the chance watch this and pay attention to the character of Mephisto. Fascinating study of this type of character in a tale. I'm too strong of a personality to be a mook. A general for either side, yes, a mook, not me. I'm never neutral about anything. If I have information I form an opinion and act on my opinions. I could see being the survivalist collaborating because I've been tricked or mis-informed but never solely out of self-interest. I could see myself being the passionate minion out of either ideology or to the FEMALE bad-girl-leader out of love! ;P I've played the villain back in my thespian days. I like the role as long as it has depth. A villain should ALWAYS challenge mores regardless of the outcome. Never be snarky about a story. Stories are what makes humanity occasionally rise above itself in majesty.
So if I vote with my head I'm likely the mentor or smart guy, if I vote with my heart I'm the hero.
It's always really difficult to imagine what you'd do in a situation you've never had to face in reality. There are so many variables to consider.
I think I'd be the person running between parties, trying, until the very last minute, to sort things out amicably and stop conflict wherever possible.
Then if everyone insisted on fighting, I'd probably be the person who's too lazy to take sides and is trying to keep out of it.
Then, if I was personally threatened or just pissed off enough, I'd be a mad berserker with complete disregard for my own safety, and probably be killed relatively quickly by someone a little more level-headed.