I was at the media event at the Qantas First Lounge in Sydney this morning and now have answers to these questions for you.
Yes, Qantas will have champagne in business class on its trans-Tasman flights, starting from Monday. It will most likely be leftover stock that was on-hand pre-covid, but it will be proper champagne. However, there won't be amenity kits, blankets or pillows available for now.
And as has been posted elsewhere, the Qantas international lounges will reopen in SYD, MEL & BNE and in New Zealand, Qantas customers will have access to the Air New Zealand lounges for now.
I've also been told that upgrading the Qantas lounges in AKL is a priority. There is no current timeline (so don't expect anything this year), but after the AKL refurbishment, it will be a combined Business/First lounge similar to the ones in BNE or LHR.