1. Even if you plan to put your kid in private school later, I'd recommend public for primary (elementary) school. Our schools in general are far better than what the USA offers.
2. The government spent 40 years telling Boomers that investing in property was "Safe as houses", so lots of them have multiple properties. Also: They allowed foreign ownership, so we have international investors buying homes here where their assets are safe.
3. Tomato Sauce is so much better than ketchup, but you can buy Heinz ketchup here if you desperately need it for some reason.
4. We don't have Mexican food. We have occasional Mexican restaurants that are good (not sure about Brisbane), but Mexican food is not ubiquitous in Australia like you'll be used to. If you love Mexican, overdose on it before you come here. I can't think of any other food examples where you'll miss from the USA.

California and South-East Queensland are moderately comparable climate-wise. You'll be right at home.