Did Aerith know?.. (SPOILERS)
That Zack died?
I mean..
http://www.youtube.com/watch?v=7jb4Ws1lPHc
See how she reacted, at the end of her scene?
And then it switches to Zack's body?
That would lead me to believe so.
But I don't think they mentioned that in the game, that she knew.
And in the short-story, the Maiden who travels the Planet, she didn't know he had died, until she saw him, in the Lifestream.
I know it's not an official novel, by Square Enix, but I heard that Tetsuya Nomura made it seem like that it was a product of theirs.