K. Napier
Comsurv is a three week course held in Townsville and the surrounding areas. It covers the three phases of Sea/coast, arid and jungle. You will be taught how to survive in these environments in peace and wartime (escape & evasion) scenarios. Expect lots of running up Castle Hill and not much food.
As Charlie Luncher mentioned above, the Defence Assisted Study Scheme (DASS) allows you to get a degree at government expense. This is done through Open Uni as a distance education course. I believe there are other opportunites to do full time tertiary study, but I don't know the details. You can apply for DASS once you're in, and you probably won't have the spare time for the first few years.
I can't help you with your questions about the maths courses or the specialised testing, perhaps a phone call to recruiting would give you a straight answer.
Good luck.
ap