According to the Mafiascum wiki, RQS means Random Questioning Stage. Is that correct?
As for those questions:
1. Well, some people get trapped in a dangerous thing called real life, in which case you can't exactly do much to change. However, attempts at creating discussion (questions, thoughts on other's posts, scumhunting, etc.) would probably be the way to go, along with simply highlighting the more idle people at the worst.
2. Probably just read what you missed.
3. In this game in particular? 50% Scumhunting, 25% Teamwork, 15% Power Roles, and 10% Luck. We can't exactly trust people very much in this game, since anyone knowing your role means you could die, you need to focus more on ousting suspicious characters.
4. It really depends on what you consider toxic. Most definitions are bad, because it is simply hostility without reason or benefit. Sometimes, people end up slipping from constantly being accused, from what I've seen in the little amount of research I've done, but most of the time, people just get feelings hurt and it devolves into nothing useful.