Interesting topic, Maggi!
In my experience, Momoko are very musical and are happy to listen to anything well done. I find that while they generally prefer cool, young music, they are still just as happy to listen to the classics. Sure they like Smashing Pumpkins, Soundgarden, Tame Impala ... but they also like Mozart and Beethoven, Lizst and Mussorgsky!
I introduced them to Jeff Buckley and they now all have a soft spot for him, and they quite like Josh Groban too. But when we listen to Michael Buble, we all agree ... why wouldn't you listen to Frank Sinatra instead?