I echo what other people have said that a lot of the exciting things to do in Australia happen outside of the cities. That said, all the major cities have plenty of good places for eating and drinking but really where you go will depend on where you stay and what’s convenient from there. I reckon if I were heading to Melbourne from overseas and wanted to see the ‘cool’ city I would stay somewhere north east of the CBD, Collingwood, Carlton, Fitzroy etc (Acrual Melbourne DISers might have other ideas but those areas are relatively central and part of the cool bit) and if I were staying in Brisbane and wanted somewhere more laid back with cafes I’d stay in West End, (or possibly South Bank if you are gonna use hotels/ serviced apartments) or if more drinking focused may as well stay in Fortitude Valley. The Valley is also the home of some of the car rental places if you want to use one for day trips.
Australia fucking loves breakfast so honestly if you only ate out for one meal a day make it breakfast. There are so many small cafes doing good coffee and breakfast food in all those areas but I could provide a list of ones I think are good if that helps once you’ve got some shit booked.
I would not go to Byron these days. If I were wanting to see a small town beach vibe near there I would prefer to go to Brunswick Heads which is very close and a little bit less like the mega rich have forced the locals out of town.
You will be here in the summer so if you do go to the Gold Coast you will want to go to the beach I should think . Don’t imagine Surfers Paradise will be good unless you are 20 tbh. I imagine your friends there will have places they prefer to go but I would say the beaches at the bottom of the GC are much more pleasant and a bit quieter. The GC hinterland is really very nice, could do some rainforest/bush walks in Lamington or Springbrook National parks easily.
If you had a little more time I would say you should check out some of the islands from Brisbane as they are really beautiful and very quickly feel like you have escaped the cities- Moreton and North Stradbroke are both very good and only take a couple of hours to get to from the CBD but you need at least one night in my opinion.
I would definitely say go on the city at and view Brisbane from the river, or walk from the Powerhouse to the CBD. The river is probably the most pleasant walk in central Brisbane. The two art galleries in SouthBank are generally pretty good if you want to do that sort of thing but I would say in Queensland I would be getting out of the city even if only for some bushwalks. Lone Pine definitely entertains my 2 year old about every 6 weeks and if you wanna feed Kangaroos and koalas , see platypus, dingos and other native Australian animals it’s a good visit for a couple of hours. A nice low key way to see the wildlife up close without going to a proper zoo.
The XXXX brewery tour is literally just a brewery tour for a shit beer company. Don’t go. There is a pleasant enough bar at the end but also there are pleasant enough bars that you don’t have to walk around an awful concrete brewery in the oppressive heat for an hour to enjoy.
Blue Mountains, Phillip Island and Great Ocean Road are all definitely good shouts on things to do outside of Melbourne/Sydney . Great Ocean Road probably deserves more than a single day, but you can definitely get to the twelve apostles and back in one (try not to get 4 speeding tickets doing so like one of my mates
)
I would say you should get the ferry to Manly in Sydney and see the Northern Beaches, they are quite quintessentially Australian even if they are fucking busy that time of year. There are also some really good walks along the coastline in Sydney if you can stomach that in the summer heat here so you could get the ferry up and then walk some of the coastline if you liked. Can definitely look up the Sydney walks I’ve done and enjoyed if you are interested in that.
This has turned into quiet a meandering brain dump, sorry! If you have any other questions about certain things I’m quite happy to try and help. I moved from Manchester to Brisbane 12 years ago, and I’ve been about a fair bit in that time.