Try posting this at the Oneworld forum

Yes. Buying a circle pacific is fine.

But try an asian consolidator who might be able to get you LAX-HKG-SYD-HKG-LAX in CX J at a special price. You'd just have to get the HKG-BKK sector seperately that's all.

Or you may try getting oneway LAX-BKK. Then from BKK, get BKK-SYD return on CX, and then buying a oneway from BKK to LAX on CX. It will work out cheaper than the Circle Pacific fare.