"A music" here would mean a type or genre of music. If you say "all musics" it means "all types of music", just as "all arts" could mean "all types of art". So it means "Would all types of music be equally effective, or environmentally “at home,” in these places?".
Other examples of the word "musics" : The album title "Fourth World, Vol. 1: Possible Musics"; The OU "Musics and Cultures Research Group"; And the Jazz magazine "Musics". These examples probably do show that it's a bit of an "arty" term.