That's a pretty fair analysis. If it's scenario 3, then I don't see how the league doesn't come down hard on the Chiefs. Well, I can see Goodell and company trying to minimize this, then having it blow up in their face like the Ray Rice incident and then deciding to issue a significant punishment.
As for other teams drinking on the premises, I remember an interview with Bruce Arians where, when he was coaching the Cardinals, he would act as a bartender out of the trunk of his car after practice. His idea for the players to relax, have a little fun, and bond with their teammates. I believe Michael Floyd's DUI had anything to do with these post-practice get togethers, but it probably didn't help that drinking was presented as "okay" by the head coach.