I know this is in the classical genre, but a lot of the music composed by Dmitri Shostakovich was banned by the Soviet government. Notably his opera Lady MacBeth was banned and Stalin had a hand in the banning. Shostakovich lived the rest of his life with a suitcase packed expecting to be arrested at any time. There is a great body of his compositions known as "top drawer" music because he knew they would be banned so he kept them in a top drawer and they did not see the light of day until after his death. Since the end of the cold war the documentary evidence concerning his life and work and his continually falling in and out of favor with government is largely available to researchers.

Tell your friend "good luck" with her project.