This is juvenile...

 Thank you. Bidu Sayao was second only to Elsie Houston (from Brasil) who had a much bigger voice but died (suicide) just before Sayao became a big hit. She was unappreciated in Brasil and had a big following in the U.S. I have to make you a CD of her complete recordings. Sayao was so sweet and lovely sounding yet small voiced.    Sample Houston - https://www.youtube.com/watch?v=6lEGux1ULH8

Gilli Smyth
Rose McDowall
Eddie Reader
Carol Kidd
Emma Kirkby
Sandy Denny
Phoebe Snow
Beth Gibbons
Carla Torgerson
Anya Plaschg
Aldous Harding
Licorice McKenchie
Caroline Kava
...

Josie Cotton, Lene Lovich, Pearl Harbor. All three had a lot of personality and musical & visual style. I was a member of Pearl’s band in 2002-3, and she is a real sweetheart. She was married to Paul Simonon (Clash bassist) for a while, and toured in the UK and Europe with Costello, in the States with Rockpile.

I had to reread the forum question.  I do not personally know the character of any of my favorite female singers that I could make an assertion that any one of them could be my lifetime mate.  I chose Claudia Muzio for her public attributes.  I like the dark sultry types of my ethnicity-maybe Roberta Peters, Rise Stevens, Jennie Tourel. Bas Sheva or even Beverly Sills....(when they were under 50 years old). 

Without a doubt, Amy Lee !