Just keen to learn a bit about different cultures in Australia and how junior development works elsewhere
I know all about League/Union pathways but am limited on AFL pathways and cultures outside of NSW/QLD.
I think you'd find most traditional footy states would be the same with the big private schools recruiting the talented juniors for their school teams and using scholarships as incentive. Examples - Lance Franklin attending Wesley College in Perth (despite being from a little country town called Dowerin) or Chad Cornes, Kane Cornes and Matthew Pavlich attending Sacred Heart College in Adelaide. There are many examples but I've just mentioned those guys to give you a quick snapshot of WA and SA. Then you have the Northern Territory situation where talented kids are often offered scholarships to attend the big private schools in Victoria and play football for them. Cyril Rioli (Scotch College) and Steven May (Melbourne Grammar) are recent examples of that.
It's a pretty similar situation in Brisbane with the GPS system, it's just that the private schools play rugby union instead of Aussie rules. Karmichael Hunt is an example of a junior that benefited from one of those private school scholarships at Churchie instead of finishing his schooling at Sunnybank High. As for the Gold Coast, it's completely different and I think that has a lot to do with a lack of history/prestige in the local private school sports competition. Gold Coast APS schools like Somerset, All Saints and Emmanuel aren't desperately trying to steal the best Aussie rules/league/union players from PBC High or any other public/state school. It's just not a priority like it is in other major cities of Australia.
It's also important to distinguish between league/union pathways and how they are intrinsically linked to the socioeconomic status of either sport, which flows into the schooling system as well. Aussie rules doesn't have that issue - it's played by anyone of any background. Therefore, it is possible for either private or public/state schools to run highly successful Aussie rules programs and I think once upon a time Melbourne High School had a very reputable Aussie rules program. However, when private schools start throwing their weight around (scholarships/money) it usually ends the same way every time and the public/state schools have a hard time trying to keep up.