Clarity to the rescue!

saraian, when Ian gets his work permit, you are entitled to a partners work permit, and the kids can have student visas. Only the WHV means you would be stuck with visitors permits.

The thing about not needing a student visa for 3 months means if you intend to take up a course which is no longer than 12 weeks, you dont need a student permit. The 12 weeks must be the complete start to finish of the course, so the kids would not be able to go to school on visitors visas, with school being a full time 'course'.