The game teams each ultimately decide how their individual games should be moderated, though Customer Support does make recommendations/offer guidance. So there are slight variations game to game - but overall the they do follow a philosophy of increasing in severity with each infraction.
No, this is not the case. Silences and suspensions are currently game account specific by default. Though, again, Game Masters do have some discretion for exceptional cases (ex: attempting to use an alternate account to avoid getting in trouble on a main account)