2) With Priiloader you can make it play games from all regions.
3) Updating out-of-region can semi-brick your Wii, so make sure you block updates with Priiloader. I'm not sure if the Shopping Channel will work either.
Since you won't be able to install anything once the Wii is in Australia (unless you visit, of course), I suggest you use mauifrog's Softmod ANY Wii guide instead. It covers more hacks, so your nephew is less likely to have any issues.