Not sure if I'm missing it, but what is your mechanism for deciding win/loss/tie in the case of unplayed matches?
Over the course of the tournament your going to have people dropout (and not tell you they're dropping) because they lose interest 5 weeks from now, but you're also going to have matches between people in US/Australia where it's extremely hard to schedule matches, as well as normal scheduling conflicts.
There's a decent chance you'll have disputes, and you should have a method of settling them (take a screenshot of you on at the given time, somewhere to post you're on and waiting at the schedule time, etc) that people know about ahead of time. What information a person should be expected to provide to not get a match loss for the round.
You should also probably give people a reminder about timezones and making sure you schedule in UTC or GMT or whatever (as well as making sure people know that "oh, we're both active, I'll play when I see you on" isn't acceptable).
You should also be prepared to give match losses and d/q people for repeated unplayed matches if you don't want this to take forever (actually keep to the 1 week limit).
Just some friendly advice from having organized/taken part in similar tournaments to this for other games.