How about this for a scenario? We know Vachon was on the plane; and he has vampire senses. What if he heard the music box, smelled the explosive, put two and two together, and whipped forward at lightning speed to grab it before it went off? He'd probably have to punch a hole in the plane (or at least rip a door off) to toss the thing out; and, obviously that would have created problems. However, the plane would not necessarily have crashed.

In that case, Schanke and Cohen would have survived; and Vachon would be added to the cast. Associate him (and Urs) with the Raven, add in his friend Screed (who probably wouldn't get past the bouncer!), and you have an intriguing new set of vampire regulars who aren't part of LaCroix's family.

Adding Tracy isn't too hard, either: a rookie detective assigned to the 96th Precinct, told to work with either Nick and/or Schanke as her training officer. That only leaves Reese....