Are these good HSC subjects? Do they scale well?

You should be able to get an ATAR of at least 90 with any combination of subjects as long as you study and do well. Scaling doesn't really matter and don't base you subjects on what scales well and what scales poorly. If you do base them on scaling and don't enjoy the subjects you choose you won't do very well and therefore scaling with only be picking up the marks that you lost because you did bad and probably end up with a similar mark to what you would have gotten with the subjects you enjoy. I've been told several times that there are a lot of people who pick subjects just because they scale well and end up regretting it. Hope this helps.