Yes
25th of December
Some do, if it's a nice day.
Australians simply greet each other with "Merry Christmas" or "Happy Christmas" on Christmas Day. Often, as one enters church, one will be greeted with "Christ is born!"
Generally, no. Hanging stockings is not a common custom among typical Australians. The closest most people get to a Christmas stocking is receiving one filled with chocolates on Christmas Day (or Christmas Eve, for some people). Some Australians do put them up, but they are really not featured as much as they are in the US.
what holday greetings do australians do on chirstmas
The 24th of December is Christmas Eve. While Christmas Eve is the most important day of the Christmas celebrations in the Northern Hemisphere, Australians don't celebrate Christmas Eve at all.
January 6th is Old Christmas Day. Old Christmas Day is another name for Little Christmas. Many different countries have different names for Little Christmas or Old Christmas Day.
Yes.
The most common way for Australians to greet each other at Christmas is by saying either "Merry Christmas, or "Happy Christmas". There is no uniquely Australian way to make your Christmas greetings.
Yes, Australians dress up for Christmas.
The predominant religion in Australia is Christianity. Regarding values, Australians believe in 'mateship', i.e. loyal friendship and standing by one's mates no matter what; they believe in giving people a fair go; in supporting the 'underdog'; and in enjoying the beautiful wild country in which they live.
Australians wear whatever they wish. In hot regions (and no, not all of Australia is hot on Christmas Day), clothing is extremely casual, from shorts and t-shirts right down to beachwear.