Late, but whatever...
I'm pretty sure she's ENFJ, actually. (Lacey Mosley/Sturm).
If you watch interviews with her, you see she’s always centered around relationships/people. She talks about how much others meant to her, who and how much has supported her, her desires and projects about how human life & relationships should be, whose words have inspired her. Her main drive is F and everything about her SCREAMS it.
A Ni-dom with Fe aux, although bothered by conflict (like she is) and relationship-oriented, would visibly have another „center”.
Just look at Tori Amos, who is typed as INFJ (I don’t know enough about her to say for sure myself, but I’ve seen interviews with her and she uses crazy amounts of N, probably Ni, and Fe, so I’m gonna just agree) who mostly speaks about meaning and symbols; when she does speak about relationships and family, it’s in a totally different way: the direction isn’t like in Lacey’s case: „I came from this place, I have these experiences, therefore this is what I have to give artistically in order to help others with their lives” = relationships+human experience before art both chronologically and as main goal. Tori does get inspiration from relationships, but she never puts her art as „servant” to people and her own healing as Lacey does. She has these ideas she wants to give life to; the ideas & symbols are the primary goal.
Another clue for Lacey: in childhood one uses mostly their dominant function. She talked once about how she loved to babysit her younger siblings (or cousins?), that it (in these exact words) meant to her all her life at the time. If she’s not a Fe-dom, I have never seen one.
Don’t type her as an introvert just because she is shy and not expansive. Functions wise she is exterior oriented, towards people. There is, I think, no interview of her without mentioning how much the relationship with someone or another meant to her or some life story a fan had told her, or something about how people should behave to each other/live their lives in order to make the world better.
I had considered INFP, ENFP and INFJ for her (because, by the lyrics and about 2 interviews I had seen at the time, she seemed N and not S; nobody could have any doubts about F), but, by watching some more interviews, I realised she definitely uses Fe over Fi and she uses too much of it and clearly dominating the importance of ideas & symbols (N) to not be her dominant function.
Anyway, I’m glad to find other people interested in her music and her type.