2. Regarding newcomers. I think the criterion for new players from other sites would be a bad idea.
3. Regarding Tournaments. I don't think it's possible to systematize Tournaments; otherwise, people will lose their enthusiasm by the time a slot opens up for their tournament. And it's also wrong to prohibit organizing a tournament when the organizer wants to. If there are many tournaments, that's only a plus: players can choose the most worthwhile ones. If there are problems with players who sign up for many tournaments and then can't find the time to play them all, I think it's only their fault and a lack of respect for other participants and/or the organizers, no matter how respected or strong the player is.
Two tournaments running in parallel are fine (and ideally, one is in the early stages, and the other is in the final stages), but more than that is too much!
Of course, it's all IMHO.