There is that - and Brienne is from an island so she could fit the whole born among salt and smoke thing.

Also the sword she got from Jaime has these weird, almost flamelike patterns, and in Jaime's dream the darkness does flee before her - like it says in the prophesy. Hmm..this is very interesting. But wha! I'm without my books here so I cannot check properly. Martin's books should come in a handy travel size.