There are psychological considerations way over my pay grade, but even with the most chill cooperative people, conflicts arise, fights break out, factions form. When you're a billion miles from the nearest police station, shit is gonna happen. People from any given current society might be wholly unsuitable because their entire worldview has a foundation unlike what you'd have in a spacefaring colony. You might have to create an isolated society, kick it off on Earth or nearby, and watch how they do before sending them off. I think, even a Mars colony is going to be very tricky for this reason. Everyone here is used to a stable society with a more-or-less reliable police force/medical establishment for the difficult edge cases.