The "red-e", "Sale" etc descriptions won't always help. You will need to get the fare class, as that is the definitive basis. I wouldn't rely on no mention of upgrades meaning that they are permitted.
There are 2 ways of getting the fare class, either some magic with viewing source on the web site (others can explain better, and there are threads around that explain it), or ringing QF or your travel agent and getting them to do the booking. Note that this won't always be more expensive than doing it yourself online, especially as you will not be after the cheapest fares. When I have done this specifically to get an upgradeable fare, I have ended up paying less than what appeared to be the cheapest the web site was offering that met that requirement.
Minimum fare base to upgrade from economy to business is "S", but this is generally not sold on either BNE or SYD to HKG, so minimum practical is likely to be "V". For upgrading to F, you will need to start with the lowest business class, which I believe is "I" if you can get it, but more likely to be "D" for ready availability.