I know there's probably a million topics like this, but I would like to find out more about this ending. In terms of timeline, Vol.2 is referred to as 0.5 (BbS=KH0, and likewise KH1 is... well, KH1), so the timeline is obviously fixed in place, but I'm guessing that whole rewinding part of the ending where it rewinds to before Aqua meets Ansem the Wise means that this is still while she roams the Dark Realm near the beginning. Now, to the actual questions, I'm assuming the castle is Cinderella's, but I don't know for sure... As for the light hole (thing which appears in the Dark Realm, does anybody know what that's all about? One more thing, I wasn't sure if those cutscenes w/ Xion & Riku had any purpose, for instance Blank Points, which just showed everybody Sora needed to save, sooooooo, speculation?

We don't know specifics on the timeline in BBS Vol 2., but we do know that it must take place between BBS and KH1. We assume that she is still wandering the Realm of Darkness, in fact, we're pretty certain. The castle is Cinderella's, so we are able to exact a little bit better the time line, that it must be before KH1. The Light hole, I'm not certain about, mostly because I can't check the scene on here because it's been removed (damn you SE) The scenes that show the one's Sora is supposed to save, I don't really believe it has much of a purpose, besides telling the player who Sora is supposed to save. Not sure if I'm right, as this is all speculation, but this is what I believe

The light hole thing might be darkness that was flowing out of the Realm of Darkness that swallowed Cinderella's world and maybe some others too. But that's just a guess.

I was replaying the secret episode the other day and I think that the holes are swarms of heartless entering the realm of light to try and swallow the hearts of the worlds and the people who live there. By 'a fragmentary passage' , the chain of events seems to lead from straight after BBSFM (dark castle of dreams) to KH1 (Goofy & Donald searching Traverse Town, perhaps moments before encountering Sora), perhaps CoM( Ansem doing research of some sort in front of the slumbering Sora), Days (Riku 'spying' on Roxas & Xion) and KH2 ( Kairi with Hayner Pence & Olette at the old mansion)..

Hey, all of your replies were great, I love hearing others' opinions of possible reasoning in the over-complicated realm of Kingdom Hearts. The Fragmentary Passage thing is still a little unclear to me, and how Aqua got to Cinderella's castle is a question for later, but I appreciate your help!