It’s amazing the stuff you find on the internet.
15 points if you can immediately name those guys.
100 extra points if you can name the guy on the right who just stands around.
And if it isn’t painfully obvious what all these people are doing, standing around and singing and dancing, here is the plot summary from imdb:
Tallulah Winters is a dancer with the Tommy Dorsey Orchestra and is asked to secretly transport a prototype magnetic mine to Puerto Rico.