HSC subjects selection help?

If you do "very well" in those subjects then you won't have a problem. But, don't forget that you can always apply for an Arts degree if anything and then you can transfer courses within the University on account of good scores within the Arts degree, that's if your atar isn't enough for your first selection. Also within the Arts degree you can do elective units within the course you really want to do and they can count for the degree you switch over to so you won't have lost any time. You can do anything you want, there is always a way.