bloodlust is on, they fight at where team gai and kisame fought. probably done b4 but im doing it anyways.
Best strategy for Kakashi and Zabuza is kirigakure followed with doton: tsuiga and raikiri, which is an effective strategy against most opponents. Problem is: Kisame is also one of the Kiri no Shinobi Gatana Nana Ninshū, and him being unable to deal with a D-rank jutsu from the Mist is hard to believe. Worse, his reflexes and combat skills leave me doubtful that doton: tsuiga is sufficient to even cause him pause ? he would probably have the physical power and skill to throw the ninja dogs off him and slash them to pieces in a spin of his Samehada.
Kisame's suiton jutsu seems, to me, to be powerful enough to overpower both Kakashi's and Zabuza's simultaneously. In close range, his combat skills also seem good enough to handle both Kakashi and Zabuza at once. He falls behind both in tactics and stealth, but as I said above I'm not sure what Kakashi and Zabuza can really achieve with that.
I think most of the scenarios where Kakashi and Zabuza come out with a victory involve Kakashi's Mangekyō Sharingan, but successfully employing that would be very hard.