Sun Lion, reading your post reminded me of something. The new movies come out on Boxing Day of Christmas week. (They normally come out on Thursday) It's common for people to go to the Cinema between Christmas and New Year.
There are all kind of Christmas traditions in Australia depending on the background of your family so I don't see any issue with the children opening presents on the 24th.
One of Leeann's daughters Sharee is from a previous relationship, the other one Michelle is Leeann and John's daughter. They didn't attend the wedding because their parents couldn't afford to take them.