I'm thinking that while she may present as a p that Bjork is an INFJ. I think this because I feel that her Ni is very strong...such strong Ni induced lyrics.
I feel most strongly that she is definately an I (only until recently (in her late 30's/early 40's) did her interviews come close to telling you a bit about her in an outright fashion. She always seemed to have a privacy issue but she opened up in the form of her "poetry" I think that she uses her art to express herself. The way she writes allows people to take it for themselves and relate it to themselves and she is still able to express how she feels. I also think that even tho she was a punk she still was always more J in her lifestyle. It always seemed to me as if she had a need for order in chaos. The N..well that's pretty obvious.