Yes, in this mod you would be able to shoot lancer as Prescott, Jace or Tai. No morebeing forced to kill locust as Marcus, Dom or Cole. It's up to you as who you want to play.
Gears of War 1 Characters:
Marcus Dom Carmine Hoffman Baird Kim Cole
Gears of War 2 Characters
Gears of War 3 Characters:
Prescott T-Cole Anya Griffin Baird Marcus Jace Bernadette Dom Samantha Cole
List of Character can change.