I was just looking up the singers listed for the Amhrain Ghra album, which appears to be intended for the audiences of the Gael Linn Cabaret of another era; the album is on the Gael Linn label. Some of these names have been considered already in this thread.

I had never heard of Marjorie Courtney, however.
In 1991, Eileen Casey interviewed Courtney for a periodical covering Knocklyon. It can be found in a PDF file online; the following quotes will demonstrate that Marjorie Courtney embraced the cabaret world.

[quote]
....it all really began when she became a pupil at the Dominican convent, Muckross Park, which was just a short journey from her home in Dundrum where she was born. 'Oh, I was so lucky,' she says, 'despite the fact that it was an enclosed order, the nuns were light-years ahead in self-development. It was the making of me....Mother Cecilia took me under her wing and opened up a new world to me....I owe so much to Mother Cecilia. She was always so thrilled when I won prizes in the soprano competitions at the Feis Ceoil or the Oireachtas...'

....her career blossomed....she was in great demand for singing at dinners -- the norm was for 6 nights a week. She recalls one busy night when she sang in the upper dining room of the old Jury's Hotel, then in the downstairs room, before dashing off first to the Dolphin and then the Clarence.
[keberoxu: must have been a weekend night?]
Today, Marjorie Courtney is in greater demand than ever -- not as a singer -- she gave that up a few years ago -- but as presenter and provider of entertainment in the grand style. She is an Entertainment Consultant....[an] entrepreneur of singers, dancers, orchestras, pipers, harpists, concerts, cabarets and show bands....

....she arranges every year, the Viennese Ball in the Berkeley Court. A full orchestra, and featured will be Niambh Murray, an attractive, young up-and-coming singer who is off to study in Italy in the New Year.
[endquote]