1). I notice that the number is very 'community inspired'. They are all working together to inspire and encourage Fred Astaire's character. They want to let him know that he can do this, and that together they can create a show that will accomplish his comeback.
2). The costuming is casual as opposed to being glitzy as it may have been in a musical number that was being staged as a 'musical number', as it were. This number is part of the story, and as such the members are dressed as they would be dressed in their ordinary lives. Nanette Fabray wears a daytime skirt and blouse, Oscar Le