I think that they are going to show three different timelines in Ep 2. Storybrooke, fairytale land present, and fairytale land before curse.
So i think that Cora is in fairytale land before curse and in fairytale land present, but not in Storybrooke. It shouldn’t get too confusing as long as Mulan and Aurora don’t show up in fairytale land pre curse which they so could. And also there will be young Snow and young Regina there, so i think that we will be able to tell the difference.
Also i don’t think that anyone that is in fairytale land present, where Emma and Snow are, can also be in Storybrooke. Not until they figure out how to realm jump again.