hey, I did music in years 9 and 10 and do business studies right now, so i'll try and help out.
1. Keep in mind that the more you like a subject, the easier it is to study for it. e.g. I dont mind doing my maths hw but when it comes to english essays, it takes so much more discipline. However, if you do still enjoy business studies, it would be ok.
2. How are your prac skills? What instrument do you play? Grade? Do you practice your instrument daily? e.g if I had taken music 2, I would be doing my AmusA for piano and there would be no way I could possibly fit in 2 hours of practice every single day, hence why I chose not to do it.
3. I found the aural part rather easy but it's different for others I guess. Practice makes perfect? Music is really subjective though, no straight answers so if you like that sort of stuff, then go for it!
4. I find that with music, it's one of those subjects like maths where you improve consistently and slowly over time, whereas with business studies you can cram in a relatively short time (which I still wouldn't recommend but remember that if you're desperate this option is available).
5. Content - i found that I didn't have to memorise bucket loads of content for music because I already had so much background knowledge. If you like learning about how businesses operate and how to establish a business and love to memorise lots of things, do business studies. Business studies is a lot like year 9 commerce (did you do commerce?). If you don't like the content you won't be able to put up with it. For me, because i find it remotely interesting, I am able to maintain some motivation to study it.
good luck with any decision that you make!