I am reposting my thoughts on BAE from a previous post on another thread:
I think it was BLUE FAIRY who sent the note and kept BAE updated as to what was happening in Storybrook and with his father.
She sent him to A PLACE WITHOUT MAGIC. I think she discovered a way to communicate with BAE ( internet/computer)
I think FTL characters have affinity for each other and are able to track each other down in the real world / StoryBrooke and every where else. That is why August could find StoryBrooke.
I also think August and Bae had known each other in the real world prior to StoryBrooke activated. That was how August knew the story of Rumple/ the blade and the Dark One. Maybe Bae and August were the LOST BOYS, part of the group of boys that ran away from the foster home. They came together over time as run-aways and disenfranchised kids tend to do.
Nonnie,