Board Thread:Theories and Speculation/@comment-25549954-20150524070831/@comment-25549954-20150527043348

Naruto had just portions of tailed beast chakra not the tailed beast themselves, he had whole Yin Kurama who could meditate and gather natural energy or something and generate chakra for Naruto. Naruto is meeting ground because he has chakra of all tailed beasts and he can communicate them subconsciously when they are physically somewhere else. I agree they are chakra monsters but they have physical forms, and they are not perfectly immortal because when they are sealed inside a Jinchuriki and when their Jinchuriki dies they also die. We don't know if the tailed beasts chakra portions can be regenerated, Minato and Kushina belonged to pure world after they met him, their chakra was gone. But the tailed beast are still present in this world so who knows if their chakra could be regenerated. In his last battle against Sasuke he could have lost the tailed beast chakra. Hagoromo asked Kurama to go back inside simply because he knew Kurama would be happy to, the other tailed beasts wanted to be free, it has nothing to do with regeneration of chakra. Naruto has both halves now as we have seen with inverted markings in the Last and he has Six Paths Sage Mode with Kurama, we don't really know what that mode is it's upto Kishimoto sensei now.

EDIT: We don't know if tailed beasts are really a criteria for Six Paths Sage Mode. Seeing the KM chakra arms in SPSM I've come to believe it is Six Paths Sage Mode with Kurama contributing large share of chakra and that is why we see Kurama mode design in SPSM.