I like the idea (in the first post).
But you should leave as little as possible for players to decide (I mean scheduling the match). Just force 3 times for each week. Like 2 for weekend and 1 for mid-week. The players would then choose one date. Of course, they might still fail at agreeing on a time, so need to force one time if an agreenment can't be done.
I think assigning a captain is a very good idea. Then there is atleast one person who is responsible of the team
. The assigning shouldn't be random and the captain should be picked by you.
Also, if it's 3v3 and teams are made of 3 players, then I am fairly certain that some matches will be cancelled or played 2v2 for sure. So maybe 4 players in team? If all 8 players show up, then 4v4, if 7 players, then 3v3 and one player can substitute. Better than 2v2 or forfeits.
I would join, but only if there are subs. I also would like to help and stuff.