About the school rank, the school rank does not affect the ATAR itself, however when giving ATAR estimates, they ask for school rank as smarter schools like James Ruse will more likely get higher results and marking reflects HSC marking. Also as they are ranked highly each year, its easier to estimate. If your school is ranked 500+ then the variance between results from year to year is much greater. There is less band 6s, as most of these schools have only 1 band 6 (otherwise they aren't ranked).
Basically speaking, if you came first, and you bomb the exam, the highest mark by anyone will be yours. This is the same for last but it doesn't matter for anyone else, as it will be modified and can quite possibly be a number you haven't received. A big misconception is that 1st place gets the highest, 2nd get second highest etc but if that's the case then things submitting marks wouldn't need to be done. Dont get hungover about this though, try your best, maximize your marks and you will be fine.
