5/10 (musical ignorance did me in). Nice puzzle!

A couple of thoughts here:
* Having two musical categories puts people who aren't strong on their musical knowledge at a distinct disadvantage; you may wish to avoid using two categories in the same subject area for your next one.
* All entries in a category should ideally be either equally familiar or inferable; one has to know a disproportionate amount about at one of your musical categories to identify all four members except by elimination.

Impossible!

Nada :(