Garaa mid difficulty.
To render Gaara's sand sand useless, the requirements are oil and water of a slippery form. Kisame only possess Water which won't render the sand useless at all.
With the establishment of Suiton not rendering Sand useless, everything else is easy to establish. Samehada has shown to get tossed around by a mere human kick. Gaara's Sand has the speed to even compete with Kimimaro who has shown to be faster than Rock Lee who managed to kick Samehada from Kisame. Gaara simply forms a sand hand and takes Samehada away from Kisame, and utilises Sand pyramid to seal Samehada.
Also, Kisame's level of Suiton is no where the supply of Sand Gaara can create. He has no way to escape them. For the water bubble to work, Gaara has to in fact come in range with the Jutsu which won't happen because 1, he is long range fighter, and 2, he can fly. This renders the fusion useless as well.
