1. Is the term 'noise and hurry' singular or plural? Is it common? There are two things being referred to: noise and hurry [bustle]. It is not an idiomatic phrase in itself.
2. What does 'hang around' mean? Is it a common usage? Is it the same as 'hang out'? What are the differences if they are not the same? Don't loiter - don't just stand about. No, it is not the same as "hang out" which means to socialise.
3. "You'll be dancing with 'em too before the night is over."
Does them refer to the people there? probably.