dear shadowhyde
congratulations to your ROP Gold!
you have many questions! I would advise to split them and ask them in different Forum or different threads
to some of your questions:
1. yes there is a fast track at SYD
2. yes both lounges open for *G
3. officially not, but most check in officers will check in passengers traveling with you as well at the dedicated premium check in counters
4. priority baggage is a complex topic...there are clear status levels that are not always reflected by tags
5. a bit tight but you will enjoy benefits; print out evidence
7. free upgrades yes if your class is overbooked and higher class have free seats and no other passengers have higher status then you (Platinum, long year G
8. no