kc_avis
No problem, I remember being in your position so am happy to help.
I would say the majority of people taken onto the cadet program did have some flying experience. I would also say experience is definitely an advantage, it shows that you're interested, that you actually like it (Adelaide is a bad place to find out you get really bad airsickness) and like I said if you can get to first solo with less than 15 hours this shows CX that you have natural aptitude. However, like I said it's not really worth getting a PPL or CPL in my opinion and I do think it is possible to have too much experience as I explained in my last post. Cathay are wanting to train you their way, it's one of the advantages for them, running the cadet program. If you have learnt a different way it can be quite difficult to relearn.
While those things you've listed are a really good start I would really recommend doing things that you can put on a CV. These don't even have to be aviation related but like I said anything that can boost your core competencies, join a sports team, apply for leadership posts at your school, start an 'aviation club' at your school etc. If there is an aerodrome near you then show up and ask if anyone will take you up in exchange for cleaning their planes, apply to aviation related businesses for internships, try and get a weekend job at your local airport etc. Do these things in addition to some flying hours.
Flight simulator can be a good way of getting a feel for flying without having to spend too much however you have to be quite disciplined with yourself, again its easy to pickup bad habits especially as you are effectively teaching yourself and these will be hard to un-learn.
I couldn't give you an estimate on how many apply versus get in, it all depends on Cathays hiring requirements at the time. Like I said 2018 / early 2019 had a pretty high intake but some years they will only send 1 or 2 batches. Number of applicants would be a complete guess but as the entry requirements are so low I would imagine its definitely in the thousands if not tens of thousands. This isn't important to you though, the only thing you need to focus on is to make yourself as good a candidate as possible so that when the time comes you are in the top X% of candidates that apply so that you get in.