Currently lv71 @22k power in S69. I am pretty much the player no one wants to fight, and my lineup does pretty good damage. Not everyone likes it though... (My server's pretty weak atm)

X - X - X
Main - X - Zabuza
Suigetsu - X - Haku
(2-2-2-1-1 )

In this lineup, you don't use Haku's barrier as a step before his mystery, you use his barrier as a buff for your Water ninjas. You could also switch Suigetsu for Kisame if you want protection for Haku in pvp.
It would look like this :
X - X - X
Kisame - X - Main
Zabuza - X - Haku
(2-2-1-1-1 )

Suigetsu is 5*, Zabuza is 5*, Haku is 4* and Azure Fang is 4*
I heard that Haku's barrier doesn't work at 2*, so try to have him at least 3*. Mine's on his way to 5*.