[combatentropy]

Yes, in fact it's two metaphors in a row.

"Once more, with feeling," is a cliche that a conductor might say to an orchestra during rehearsal. Presumably professional orchestras usually play with feeling, even on the first attempt. So the conductor means, somewhat condescendingly, more feeling. It has been said so many times by so many conductors that it has become a running joke. If you were doing a comedic impression of a conductor, you might insert that phrase.

Four-part harmony is the performance of a song by four singers (or four groups of singers): soprano, alto, tenor, bass. You could have just one person sing a song, but if you have a whole chorus sing it, it will sound fuller (though not always better).

It was a funny way to say that the bank not only will require the money from the person who began the transaction but also will impose severe fees.