CX888 is certainly permitted on an XONEX, and offers much better service than SEA-JFK on AA, which is your other option from that part of the world. Depending on which frequnt flyer program you're with, an if you care about the 2000 or so miles, might help make your decision for you.

The other thing is that you should be carefulo about purchasing the extra segment to go LAX-(HNL)-SYD: unlike in previous years, now, if you reroute an XONEX, and the new routing doesn't include the extra sectors (or continents), the extra fare paid in now NOT refundable. I was sorely disapointed when this new rule kicked in, and I'd hate for you to find out the hard way.

good luck with your trip...