Enigmatic_Paragon saying that Haku had to be ANBU is an assumption, you can learn about the bodys lay out in places other than ANBU training. Kakshi belived he was ANBU but that doesn't make it a fact. Also Zabuza closed his eyes in the mist as well giving him a disadvantage still because when they got close they could see each other, or rather Kakashi could see him making it worse close range than Gai's (if your using hand to hand only then the ability to see his feet from far away vs not seeing anything wouldn't make a huge difference either.)
Naruto has working brains, you just don't seem to get it(ironic eh?) he may be loud and noisy some times but there is a reason he is the #! ninja at suprising people.