I don't know if this answers your question, but they have the "Music listening stations" in the Lab. They're kinda like a jukebox with headphones. It's just a keypad and headphone jack. Usually nearby, there's a list of the music.
No, they're free. They also have them in other areas of the ship. I know sessions has some by the window seats. I suppose they're other places too. Just look for the "Walkman" style headphones.
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!