This special appears to be valid for CNX as well departing mid February and returning mid March. It prices ~AUD664 for each adult earning 2,794 Asia miles each and ~AUD150 for infant. Total ~AUD1,470 which is a pretty good deal.
Looking at Qantas the best I can do to BKK is ~AUD1,660 earning 10,400 QFF points and 5,200 QFF points for Bronze and then another ~$350 to CNX.
But there appears to be a catch with the CX airfare. Unable to pre-book seats. There is a possibility that we will not be able to get bassinet for baby? Is an ~AUD600 saving worth the risk? Flight would be torture without bassinet for baby.