It sounds like the dates are set, only your attendance is tentative. If you are willing to pay cancellation fees if the gig falls through, I would look to book now while US offers 110K in business or 80K in coach to Australia with a free stopover. Book to BNE and back on some combination of JL, QF, CX, AA and US (US routing rules are, for now, wide open. learn to search for segments at ba.com if you don't already know how) with a stopover anywhere you like in Asia. If you on CX you may be able to also work in a day in HKG. Then book a separate ticket using UA, US, DL or a combination of AA and BA BNE-CNS-NZ-BNE. US would be only 25K for that roundtrip with a stopover, UA would be 35K, DL would be 60K but may have much better availability on Virgin Australia. US could change their program to line up with AA at anytime, and DL's rules starting 1/1/2015 are not known. If you can put that together, I would book now unless the fees would be a huge deal if the gig falls through.

Feel free to add a post dates and plans if you're looking for help with segments. Good luck!