So addressing the 2nd part of your question first. First class wine is double catered on the QF1/QF2! So nothing to worry about there.
In regards to catering in general, I imagine what has taken place, would be the flight is double catered. A huge task to pull off at short notice.
QF has done this before. A few years ago, JNB caterers went on strike, and QF was able to double cater a 747 to ensure two meal services in both directions.
This would mean a reduction/change to the service in all cabins in order to get it to all fit. They can also do things like pre-setting water bottles which gives them more space again (that would free up 2 carts for food). From memory I don't think any A330 aircraft visit Darwin, so they would mostly have 737 equipment which is not compatible with the A380 so all the more reason it will be all loaded ex SYD. During the refuel, they will probably only change the bins and clean and empty the toilets.