Always wanted to see this fight. Honestly can't say for sure. People tend to underrate Haku alot for some reason. It's like a clash of opposites. Kisame has big flashy and potent moves, while Zabuza and Haku are more subtle and target vital areas for easy kills. Don't think samaheda can heal kisame if he loses his head, but Kisame is probably also used to fighting in Zabuza's mist. Haku can probably freeze Kisame's water attacks, but i'm not sure if sh- I mean he is that skilled with ice style yet or not.