If you have one player on pass and one player on don't pass the house still has an edge on both bets. In the case of the comeout roll with a 12 the pass loses but the don't pass is a push.
The math is pretty easy on this one. You lose .5 of a bet every 36 rolls.
.5/36 = 1.39% house advantage
Druff, let us know when you receive redietz’ credit score.