This is actually so much fun and thank you everyone for all the tips and help

Good point on the value of SPG. I am not so worried about hotel nights at the moment as those are much easier to get than flights and I estimate we essentially have another 6 months to collect the hotel points. I was able to get rooms for New Year's in Rio this December 3 months before. I will probably have to do some more research, but we are preliminarily thinking of doing 4 night AXONs in Cairns and Sydney (Cat 5 and Cat 7, respectively). Our agreement is also to have the SFO person use points for hotels since she travels for work short distances and has few airline miles.

I was working on this some more and did start thinking about the fact that I am using SPG for the US Airways flights so it's not really 110k US. Also, it may be best to try to go for the Qantas business class ticket on AS (which is really really hard to get, but I have a backup plan).

Would it be crazy to actually go with 135k UA for the business class ticket from NYC?

The things is US already charges $50 for an international award and you pretty much get only on shot at it with each additional change $150 (unless there is a schedule change, but with common routes like JFK-ICN-SYD, the schedule is probably pretty set). I am 1k on UA so can change all I want, which I will most likely want to do if a North America - SYD flight becomes available. Moreover, since I am not doing any stopovers on the JFK-SYD round trip and United does allow me to add a stopover and open jaw (whereas US has stopover OR open jaw), I can add another segment for another trip beforehand from the Caribbean or, if I change my mind later, change to a stop in Asia - just with booking tickets so far out, changes you wish you could make for free are likely! So $50 processing + $150 to change + North American segment in business from elsewhere = all these differences may just make up for the 25k miles

So now I have the following plan:

1. NYC: Move 60k to AS as eattofly suggested to try to get the business class flights on Qantas for 110k miles and put intra-Australia flights on Qantas also. If this doesn't work (which it likely won't), use 135k UA for the ticket JFK-SYD and then do little flights with BA within Australia.

2. LAX: Use 75k AA for the ticket LAX-SYD doing a north american stopover both ways. By the time Qantas inventory is available on AA, the flights may be gone so then will try to take Air Pacific or HA, maybe building a 24 hour stop in Fiji.

3. SFO: Use AS miles for the ticket from SFO (preferably on Qantas, but lots of other partners, such as Delta, Air Pacific, Cathay). If option 1 does get the business class flight, then use AA miles preferably overlapping the route with LAX person.