You make great points I agree with them all, the first point is very interesting almost seems like this is where the future of NRLs demographic lies. I do think participation for AFL, NRL is hugely important as they are the 2 main professional sporting codes in the country, Cricket probably used to be up in that category with them but from my perspective it seems to have dropped right off just looking at crowds and maybe general interest and coinciding with this i couldn't name one kid in my kids age group that plays cricket. As for soccer and basketball i think they suffer from the fact that to go and see the absolute best of the best in those sports play you have to go overseas to watch or tune in at early hours of the morning, I do think that is why the local leagues do suffer as they are always perceived as being a much lower tier. Something AFL and NRL don't suffer from.The Pacific Islander juniors have been an issue for league for a long time; because of the nature of the sport, I'm not sure if there's actually a solution for them.
AR is also a contact sport, but its nature as a sport is that it's in the middle in terns of perceived danger. I dont think parents are totally against contact; but there are limits to how much danger you expose them to. So while AR might suffer a bit from contemporary understanding of head injuries, it won't be as much.
That being said, while participation is important, it's not everything. If it was then basketball and soccer would be huge here; but the national comps seem to go in and out of bankruptcy a fair bit.