Sound 4 get blitzed the same way they got blitzed by Kimimaro, a kage bunshin using raikiri is enough here.
The original kakashi finish Kabuto low diff.
In part 1 when Sasuke was in bed, When Kabuto ran away, Kakashi's conclusion shows how he overstimated him because of what he did on the anbu fodders and how he escaped. He hasn't show anything special that time, yet Kakashi overstimated him and thought that he needed to train to compete with such guy because firstly he had no knowledge about Kabuto, he realized that Kabuto was not a simple genin and he was under Orochimaru's command whereas Kabuto had infos about Kakashi and yet prefered to escape twice, it talk by itself and comfirm his fear and inferiority because he know that it would be an extremly bad match up for a close range fighter as Kabuto who is slower and less skilled than a ninja who mastered the sharingan with a lot of skill and versatility.