In my experience, the answer to this is probably yes you can, but you will have to call QF and ask for what you want by specific flight numbers. I have done similar things eg flying CBR-MEL via SYD instead of direct when it suited me but not for a while. A couple of cautions:
- mention frequently that this is being changed because of a QF initiated flight cancellation - stress that the change is involuntary on your part. You will need to use the word involuntary as many times as you can.
- Tell them that the QF proposed new flight as a result of the involuntary cancellation of your original flight does not suit you but the preferred flights you have (with accurate flight numbers) will work for you and you want to be changed to these flights at no cost to you as the changes are involuntary.
- check that they are keeping it all on the original PNR (which is how you keep the DSC) and stress how important this is to you.
- I've never done this myself, but others suggest asking for a copy of the recording of the conversation so you have proof of what you asked for in case there are any stuff ups.
- If you get any kind of bad feeling at all that the agent does not understand what you are asking, HUACA.