How many GCSEs do they sit are your school? Mine do 9 and only have 3 options because all do Eng Lang&Lit, Maths, Double Science, MFL (which they choose in Y8, mine do Spanish). If want to do triple science that uses up an option slot.
I'm a mean Mum with academic children so insisted on triple science (school strongly encouraged as well), both love science and are now planning on doing science A levels. I also insisted on geography or history to keep options open, one did history, the other geography and both love those choices.
Then one is doing art and the other is doing music. Art takes up a lot of time, DD1 is expected to do very well but she has done art for pleasure for years so it's not been too hard for her and she does love it. But agree with a PP, they've been repeatedly told it's incredibly difficult to get a 9 in art.
The musician has two music tutors (piano and singing), sings in the (excellent) school choir, performs in the school musical each year and plays the violin in a regional string orchestra. So does a lot extra, I think music would be very hard if you couldn't read music and didn't have an understanding of how orchestral pieces are put together.
Incidentally a friend of DD1 did 3 arts subjects as her options and now regrets it, particularly that now she's a bit older she's getting more focussed and sensible career ambitions. I think if you have academic kids the best thing to do is encourage a good mix of STEM, humanities, MFL and arts to keep their options open.