Regarding the moderation process, it would be favourable if the performance standards of your cohort are high, which is something you can contribute to by helping your peers. If this is attained in all/most of your school-based assessment tasks/exams (i.e. internally) and taken a step further via good overall performance from your cohort in the HSC exams across your subjects, it will mitigate the risk of receiving a lower Assessment Mark, which contributes 50% towards your final mark (i.e. HSC mark) for each of your subjects, in the event where you receive a low/unfavourable rank final rank. However, considering your ranks, I doubt you will be affected by this, particularly in Biology, Modern History and Legal Studies. If your final rank in those subjects ends up being first, then your Assessment Mark will be adjusted to equal the highest Examination Mark (i.e. HSC exam mark, which contributes the other 50% towards your final mark) of any student in your cohort.
I hope this helps!