Too many games too little time
PV stands for Promotional Video :3
In Re:coded's secret ending it was stated that once the Heartless and Nobody of a person is destroyed, the Somebody comes back into existence. (Also in the KH2 novels released years ago, Naminé gave similar information about Nobodies and Heartless, and inferred that Axel might have returned into existence) We can assume that Lea's Heartless was destroyed, so once Axel faded away, Lea was able to return into existence.
Hope that helps!
Signs of What's Next said:YS: Hmmm.... The question is... What does Xehanort intend to do next?
*dramatic music starts playing*
M: Xehanort? But his two halves are gone... There was Ansem, who commanded the Heartless...
*gestures with his left hand, ghostly image of Ansem, SoD appears*
And Xemnas, who commanded the Nobodies.
*gestures with his right hand, ghostly image of Xemnas appears*
Didn't Sora defeat them both?
YS: Correct, those two met their end. However, therein lies exactly our problem. Their destruction now guarantees the original Xehanort's reconstruction.
YS: Xehanort's heart, once seized by his Heartless half, is now free. And his body, which had become his Nobody, has been vanquished. Both halves will now be returned to the whole. In short, this means Master Xehanort will return...
*camera slowly pans right, ghostly image of MX appears*
I wish more people used these... I worked hard on them.