Related question, I have a specific flight I'd like to take (so as to be with another companion already booked on revenue) on CX. The award for the one way flight in economy is currently unavailable but it's in Feb 2016 so plenty of time left.

I have just enough AM to redeem, but would prefer to use BA Avios since it's only 4500 vs 10000 on AM. Can I still waitlist on AM and when the seat becomes available book it via BA? Will there be any email notification from CX about the availability, and can I at that point cancel the waitlist? I'm assuming based on the above I won't be charged cash or miles.