No matter whether BF is evil or not, I’m convinced she’s manipulated characters for the sake of a certain outcome. We just don’t know her exact motivations.
BF in the diner scene in Darkness on the Edge of Town really made me think she’s in league with the Sorcerer. I really like the idea that she’s out to destroy the dark one curse.
Also, I read some trivia that A & E wanted Lady Gaga to play the Blue Fairy originally, but it didn’t work out. Asking Gaga to play BF could possibly mean 2 things: 1. This character isn’t that important and we won’t need the actress often, or 2. We need someone who can make the BF a monster as the story develops.