If my passport expires 2months after we travel and return from Cananda is that okay? Or do we need a new passport that has at least 6 months validity after we return?
Canada, in general, does not have a requirement that passports be valid beyond the return date that the traveler has booked, so you should have no problem.
Australia to Canada doesn't have such restriction 6 months validity.
You can travel with passport expiring in 2 months.