Thanks guys, very useful.

I am indeed looking for an award ticket but I don't really care if it's Business or Economy for a short 3h flight AKL-BNE or AKL-SYD

As for the direct from AKL: Yes, the United seasonal work with my dates (Feb 2018). And the connection with the AC flight at SFO works very well (United arrives around 6:30 and AC depart at 8:15, both direct).

But given I never see the AKL-SFO on the Aeroplan website, I'll secure SYD-YUL with AC first and then either buy/get reward AKL-SYD "last minute" a couple of weeks before the flight. IF AKL-SFO UA opens up I'll just cancel the other one.