Hinata = Tank
Naruto = Off Tank
Shizune = Healer
Water = Healer / AOE (with sharks)
This is my personal opinion tho, maybe replace Naruto with a DPS/Damage Dealer, as Kakashi (Glass Cannon) or Sasuke, but it depends on the combo with main water. Put your formation in the Simulator and replace Naruto with the ninjas you have and see if the combos are good. By the way, don't forget to change Talents on Simulator.
Here you can pick Water Main
http://image.prntscr.com/image/457cef9bb74f4ceb83d74a095a601b63.png
Here you can see Possible Combos for your Line Up
http://image.prntscr.com/image/6253e806f4984ba28237f22e99a88c5d.png
And don't forget to set up your talents
http://i.imgur.com/cRGN3CR.png
Good luck !