I recently came to the realization that kicking off with Ghast or Casket (which had been my previous inclination) wasn't nearly as impactful as kicking with Scalpel.
I'm a primarily Scalpel Morts player, and I tried kicking off with her for the first time this week to find that she presented a huge takeout/goal threat to my Brewers opponent. He recovered the kickoff with Vet Spigot, passed to Friday and had to make the decision to either keep the momentum or dodge way back behind his own deployment line. I felt completely in control, regardless of his decision - if he stays put, I can charge in and make my move on the goal; if he dodges back, he's pulling his central striker away from my goal (and I can still jog into Spigot for easy momentum).
In the end, he decided to stay put. Scalpel moved in, generated a bucket of momentum and scored - then dodged into a position where only Friday with a couple influence could reach her.