Honestly, all of these girls fall into 3 categories for me: (1) not interesting enough to merit a biopic, (2) have already released some sort of biopic/documentary of their own, or (3) their twitter output and musical over-sharing has already given me more insight into their personal life than I want to know.
Mariah Carey would have an interesting biopic, also.
I was going to say Mariah too, but come to think about it she has a typical female artist story like Dina from Dreamgirls, how she was controlled by her husband/manager.
(?) They're not listed in the OP, stop trying to ruin the discussion.
Anyway, DEFINITELY P!nk.. the parental abuse, living in the trailer park, almost getting murdered in Rome, being chased down by cops, & when she was drenched in puke at her prom.