I might be the one that's wrong here, but I swore people were using Wiimote for it in multiplayer. Sadly I haven't had the chance to check it out yet with other people, just watched videos of it pre launch.
nah, you are correct. ZombiU multiplayer is played with 1 player on the gamepad and 1 player using either a Wii-U classic controller pro or Wii remote+nunchuck setup.