1. Yes, the use of comedy throughout the clip (the doorman, the competitive glances between Ziegfeld and Billings, Held's back and forth over the pretty flowers) depicts a carefree life in what we know to be a turbulent society at that time.
2. I think what was mentioned in the Daily Dose summary is more of what we would see in other musicals including the friendly competition over a pretty starlet. The familiar comedic relief of a bumbling doorman or other small role also springs to mind.
3. After listening to the lecture and reading the summary I would expect to see more skin and scantily clad women in a behind the scenes/backstage/dressing room scenario. And the star of the show would more than likely be singing lyrics full of innuendo.