There is one handy explanation for all of the under-explained back-stories and the unresolved plot points in the game: If the entire world and all the events in the game truly are all products of Cyanea's ongoing dream, then all of the loose ends in the story are due to the fact that sometimes dreams just don't make any darn sense.
The Kids in the bus are a rich mine of this. First of there the fact that they seemed to be gone enough for years, enough for their crash to be an Urban Legend, and likely more than enough to cause their parents to think they were dead.
There's also their ultimate fate, they are still on board the ark, sleeping. Now apart from that would had caused them to enter hibernation in the first place, the other part is when and if they will wake up. Unless the ark, Cyanea or some other aspect of the dream keeps them in stasis, these kids would be dead in a few weeks. Then again we are talking about a dream here.
Then there's Raven. If she is Zaza's sister Than why does she look older than him now? (Apart from spending time in the city). Also, her brother is asleep along with the other kids on the ark, unaware that Raven is his sister, that's bound to cause her some heartache there.