DS looking at doing Music, Psychology and Maths. Probably. Encouraged by school, and also personally keen to start with 4 with a view to dropping one once they have a proper feel for the A Levels. Other possible subjects would be German, Sociology, Economics, Art, Further Maths, Eng Lang.
Music, Psy and Maths are not an incoherent mix, but they do not have content overlap in the way that Geog/Sociology/Ec or Maths/Phy/Comp Sci do. Still, it must be best to pursue what most interests you? DS potentially looking at a Music degree so subject mix isn't really an issue (but could change their mind!)