Many thanks, Chris E and Geting! I don't like to enter solutions without justifying them, but all is now clear! Unfortunately, I was trying to work around "ST" for saint, and not just "S" - It's the same with "circa", which can be "CA" or just "C".
Chrise, she's one of my absolute favourites; a true old-fashioned R&B and Soul diva of the 1970s 1980s before moving into Gospel. Lady Marmalade is her best-known song for the non-aficionados
I’m quite sure rusty has the intended reference. Not least because I believe the Times has a convention that it doesn’t include references to the living in its cryptic crossword clues