I recall it saying in the manga that Zabuza and Kisame fought once, but I read it like a few days ago and often forget what happened a few minutes ago, so I could be wrong, but if Zabuza were mentioned in the story, it would probably be to give some more info on Kisame's past, like he'd appear in a flash back or something. And Zabuza weak? Put down the drugs, you speak as if he was killed by Naruto or Sasuke, he was taken out by Kakashi, who is no joke, compared to someone like Orochimaru he may seem weak, but that doesn't mean he is weak.