Could Lily be the black fairy? Her star was black plus blue fairy is known as blue Star.
This was the exact though I had as soon as I saw Lily and the star mark. I’m not sure why I thought this but The Black Fairy has been mentioned at least twice now and her wand was mentioned too also this was in context with the Blue Fairy and I think Rumple too if memory serves well. Also since the books author is being hunted down it seems like many have suggested before that it is like the end so why can Black Fairy not be brought in now, maybe this has some relation to the book – The author and Black Fairy
Maybe the star is the mark of evil or something and after being rejected by Emma the ”evilness” inside Lily is activated and she realises she has magic. Maybe Blue found her and knows Lily and her story. What if Lily was taught the ways of being a fairy and had access to their magic and knowledge but is in fact a human being and because of this turned away from Blue and the others, I’m reminded here of a version of Snow White where all the dwarves were dwarf sized but one was tall as a human would be or think of Elf.
Keeper of a few things which I've forgotten but I know I have dibs on them