The songs Maude and Jane sing in the beginning of the episode are "Waves of Danube" which is also known as "The Anniversary Song" and "Button up your Overcoat".
During Maude's conversation with Florida (with Maude stating that her whole life could be sponsored by Proctor and Gamble), the audience disappears for a few moments, indicating that a flubbed line had occurred (which was reshot as a "pick-up" after that night's performance had wrapped after the audience had left).