EDIT 2: Looked a little further and Rick's special ability is getting one hit kills. Vehicles blow up with a few shots, too. Niko's depression special ability freezes time, allowing you to gain health for every kill you get and slow down every character on the screen but the player, allowing you to move quickly in a slow motion world. Michael stays the same except for a color change for his ability.
This seems like a crazy dlc, are you sure this isn't just some made up stuff?