Continuing with the Greendale "Community" posts...
This idea seems to have a bit of traction. I've played in a Red Dwarf freeform, where multiple versions of Lister, Cat, Rimmer and Kryten were running around in a reality bubble on the edge of a black hole. This game had all of the alternate versions of the characters encountered during the show...the ultra-good, the ultra-bad, the gender swapped versions, and then a few characters who are integral to the plot but who don't make up a big part of the show "Kuchanski", "Peterson", etc.
It was a great game in the Aussie freeform style. Everyone has a half dozen agendas to fulfil during the course of a three hour session, each of those agendas may be working with members of their team, working with alternate versions of themselves, or working against people. Often tasks require careful planning to orchestrate and may only be viable at certain times within the session (eg. Only when the ship's fuel drops below critical level an hour before the end of play...unless someone sabotagues things to occur quicker), sometimes tasks require a certain amount of time to accomplish (eg. Shagging another character is done offscreen, and both participants are out of play for ten minutes while the deed is done).
There isn't really a mechanism to determine success or failure, you just have to set up the deed and if there is no-one to oppose you, then it happens...if there is someone to oppose you than you need to find a way to circumvent their opposition. If you need to fix something, you need the right tool, which means you might need to negotiate with the person who has the tool, which in turn might mean that you need to help them accomplish their goal. Everything in this style of game requires talking with people, and every time you talk to someone you learn a bit more about their agenda within the game. Sometimes you learn goals that you have in common, and sometimes you learn goals that might come into conflict.
If I was going to apply a mechanical system to the 'Greendale' game, I might go with a streamlined version of the Mind's Eye Theatre rules. If you do something, it happens...if it's opposed, then both players play scissors-rock-paper...if it's opposed and there is a tie, compare stats (sometimes a character might have a skill that simply lets them win on ties, or might have an expendable token that lets them win a single challenge if they are willing to sacrifice it).
Unless we were running a 'Greendale Paintball' session there really isn't a lot of physical combat in the game, so things shouldn't draw out too much. If I was running a 'Greendale Paintball' session, I'd give everyone a NERF gun...that allows combat to play out in real time with minimal chance of injury.
The key to this style of game is providing an ecosystem of conflicting choices for every player to engage with, and a variety of events that engage different styles of play. A bit of politics, a bit of teamwork, plenty of humour, some external threats that everyone can react to, and key events that tilt the play environment in some way.
The story in this style of game is given an impetus direction at the start of play, but where it goes once the players get involved is entirely up to the will of the masses. The GMs purely act as facilitators for the events in motion. The great advantage of having a tabletop session before hand comes from careful directioning and placement of goals within the first part of the game.
I haven't specifically determined a story yet, but ideas are bubbling away.