Hiraishin, one way or another, was used to deal with the tailed beast ball. The 4th didn't become Hokage by being skilled in any other ninjutsu than space-time ninjutsu. Fuinjutsu... Meh, not as much I'm sure.
Anyways, I thought the other half had already returned to Kurama when the belly of the Reaper was cut open. In any case, I can also imagine Minato coughing up (no pun intended) kurama's yin chakra to replenish its strength and get them fighting again.
P.S This also means that Sasuke is back into the scene next chapter, and I bet he and Naruto are gonna work together. Or the Hokage will take the mantle and start something.