Its a shame you are starting in MEL :cry: . Not only because MEL is MEL, but because you cannot fit MEL-PBI and return to MEL into the 22,000 mile limit of a OneWorld Circle Pacific fare. So that would need a DCIR26 fare costing about $1500 more, but giving more options for maximising SCs.
For a DCIR26 fare from MEL, try something like this:
MEL-SYD-AKL-LAX-LAS-SFO-DFW-PBI-DFW-YVR-HKG-SYD-MEL
or
MEL-SYD-LAX-LAS-DFW-PBI-DFW-ORD-SFO-HKG-MEL
Both of these have the advantage of using Cathay Pacific over the North Pacific routing. Using AA to NRT is shorter, allowing more advantage to be taken on the AA domestic flights in First Class earning F SCs.
If you can start and finish in BNE, and use FLL or MIA instead of PBI (PBI is only serviced from DFW, while FLL and MIA are services from DFW and ORD), you could do:
BNE-LAX-SFO-DFW-FLL/MIA-ORD-NRT-BNE and fit under 22,000 miles. Then spend the $1500 saved on a MEL-BNE-MEL fare from the current D class fare sale.