If you insist on staying with Zabuza, I would replace the obitos with two copies of vanilla Haku. He's a very strong early game play and would allow you to go into the Zabuza Haku squad. It's quite a beast and it allows you to move support to other teams.
If you go with kakashi as a 5 drop then I would recommend replacing boyhood with a copy of Sasuke [Desperate Avenger]. Access to Susanoo is never a bad thing. Being a water fire card also helps. Since Danzo exists, you'll never be stuck with a Sasuke on field either. Even if you have a Sasuke/kakashi squad that can be changed to a 9/8 Danzo and put DA in play