Well I've been able to get Suno to do Beatles covers. It only works maybe 1/20 times, but you can do it. It's not an exact replica either, but you can get the same chords and melodies as the original.
Well there was that legal company who trained an LLM on their oppositions legal documents and then generated their own. I dont think inputs or outputs were ruled legal in that regard.
But as long as the model isnt outputting infringing works theres not really any issue there either.
Claude has been considered transformative given it's not really meant to generate books but Suno or Midjourney are absolutely in another category.