omg I had no clue you could send them new music either!! None of my villagers have really... unfitting music (they either have ok music or just keep selling their music players >:^( ) but I'll def try this sometime!!!
If mine don't have radios, that's the first thing I send to them. I like music in all the houses. Lolly was really stubborn about getting rid of tabletop music players, but she's kept her turntable and then jukebox ever since she got them from me.
I gave Pietro some random KK song to replace Parade because I had a near-mental breakdown the first time I entered his house. I sent him a very strongly worded letter with it. He is not to use that song in MY asylum.