Rok2id, I'm glad you brought in the girl singers, this conversation would be incomplete without them. But you left one out that deserves to be ranked alongside the one's you mentioned, and to be placed in the company of those ladies is the highest of honors for a girl jazz singer.
Anita O'Day is one of the "jazziest" girl singers. Check her out on youtube at the Newport Jazz Festival singing "sweet Georgia Brown". I've never liked that song, but when Anita sung it at Newport, it was too hip for words, even the way she moved was jazzy.
A girl singer is known by the company she keeps. Duke Ellington, Oscar Peterson, Dizzy Gillespie, Miles Davis, Stan Getz, Gerry Mulligan, Coleman Hawkins, and Stan Kenton was some of the company Anita kept.
I like your list, and as I read it, I pictured that particular girl singing one of the tunes she was most famous for.
Conversations like this about the music I love, really makes my day, and I hope it makes yours to.