I think the enchanted forest thing is a dead giveaway that somehow these three are either the enchanted forest counterparts from the past to save the future of these three are separated from all their family in the premiere and end up on the Enchanted Forest.
Why would characters in the past be in the future? So we have time travel for just these three characters into the future to meet up with a present day Henry in the future?
Henrys Author powers perhaps. He can go back to specific parts of the book.
I think something has clearly happened to separate these three from their loved ones and maybe Henry Lucy and these three team up on the EF to fight the evil and save both realms to return to their families on SB.