Wait a minute. What shows that FRS could hurt the Juubi. From what I'm seeing of the scan, it was a FRS-ENHANCED AMATERASU that merely hurt the Juubi, or at least it caused it to screech from the flames hitting it.
Naruto's Normal Rasen-Shuriken cuts off several tentacles of the Juubi
FGT >>>>>> Rasenshuriken. So Dangai Ichigo is more than enough to act as a decoy while Yama attacks it with North.
Individually they can't win, but with proper team work they can