As is typical of when a new trailer comes out there's some new info via developer interview on the PS blog.
In it, Nomura confirms that Rebirth ends at the Forgotten Capital/City, ie. when Aerith does or perhaps does not leave the party.
However...they also say that although the majority of places from the original game will be here, and the player will visit them, the order may not be the same.
So, it's possible then that the story will take you to the north crater and we'll see all of those events, plus more, with Aerith in the party.
It's also unclear who exactly is playable in Rebirth. There's reference to some characters not being playable, so it's possible the likes or Vincent and Cid will be like Red XIII in Remake, or it could be a reference to Zack.