i see 6 tails, but i assumed he had 7 out by that time, until he whips out the 8th that transforms him completely.
I would think that every tailed beast can heal since they want the jinchuriki host to survive, their own survival depends on it. It's just that the 9 tails can do it at a faster rate due to it's massive amount of chakra.
Looks like 3 tails to me as pointed out by shikamaru-sensei.
I think all bijuus can heal. I think when the chakra encompasses them they heal. It is chakra that heals people faster. Like medical ninjas redirect chakra to heal.
I am McLOVIN
from how i see it, i think that the tails were serving, and it is in motion but just my opinion.
Easiest to see that its 3tails from the pic where 8tails was lying on the ground.
Orochimaru for final villain!