Originally posted by: KM
for the kakashi vs haku debate:
when kakashi said there are people stronger than him and younger than naruto, he was referring to haku. But he did not know how strong haku was. He was just saying it to teach naruo a lesson. Haku was dressed as the equivalent of an anbu of the konoha. The mask that he was wearing suggested to kakashi that he was at least stronger than a jounin (and haku is definitely stronger than zabuza). That was why kakashi made the assumption that haku was stronger than himself.
Based on the look, you would expect haku to be even stronger than itachi, since itachi was some years older before becoming an anbu.