Well there are two possibilities here that might explain the discrepancy.
Possibility number one, that since outsiders weren't able to easily enter Storybrooke it might be considered an extension (of sorts) of FTL, or something, that would allow a special exemption for Cinderella's baby.
And/or Possibility number two, that Storybrooke is a little bubble universe that possibly only left the FTL natives with memories.... Erasing Storybrooke from existence has undone things to the FTL natives, so Cinderella is now again 9 months pregnant about to give birth. That possibility also leaves the chance that some dead characters are alive again in FTL, with memories of Storybrooke up until their death. From the Sheriff to Gold. Though Pinocchio would likely 'remain' a kid (while he wasn't afflicted with the curse the first time around, apparently Pan, Neil, and probably Ariel and the Lost Boys, are affected. In this scenario does that mean Pinocchio will regain lost adult memories??? At least I assumed they were lost based on the atmosphere of that scene when he went back to being a boy...).
Hopefully for Cinderella's sake they aren't both true and she doesn't end up with the strangest origin story for identical twins ever (there could be an argument for both being true being more inclusive... It has been a while since the curse was broken and time started again, we don't know everyone in town and someone could have conceived, and possibly even given birth, to a child since then. If things are 'completely undone' then Cinderella is still pregnant and any child conceive after time started again is lost to the ether.)
I also don't know what affect cancelling the curse would have on the non-FTL normal folk that have come into contact with Storybrooke. The kid and his father camping when Storybrook came into being (did they ever definitately show what happened to the Dad?). Neil's dead girlfriend. The Darlings.
ETA: Speaking of the Darlings... Where the heck do the Lost Boys "belong". FTL folk may 'belong' in FTL, but those lost boys come from all over. Even if we say all other 'universes'/'lands' besides Earth are FTL the shadow was taking kids from Earth too.... Unless the when Neil first met the Darlings wasn't on Earth, it just looked like it, but I am pretty sure the episode did specify England. So is the promise of giving the Lost Boys a home going to be broken, albeit unintentionally? Do they all go back to Neverland alone (or worse, with a revived Pan if Storybrooke events are undone). If the earthling Lost Boys do go back to where they belong *originally* is that not just in "space" but "time" as well? Some of them weren't 'stolen' from good homes like the Darlings one would presume and may prefer to stay with the Storybrooke folk. I doubt we'll have follow-up, but I could almost foresee a former Lost Boy wanting revenge for them cancelling the curse!
Edited by sierraleone, 18 December 2013 - 10:59 PM.