I saw an interview with Kitty Carlisle in which she said that really was her voice in the movie. Apparently she was an opera singer as well as an actress. So yes, that was her all right.

I was pretty surprised. I grew up watching her as a celebrity guest on game shows and had no idea that she was famous for anything else, but immediately recognized her name.

Tell me the name of that piano book. I'd like to see a copy.

The piano book is from the Alfred Piano Series. I believe it is book 2 and it is brown. It is at the introduction of playing the pedal.
It is great that we can still see the old movies. I loved Groucho also. I can remember my Dad laughing at him when he was on TV.