1 hour is, i would say, cutting it too fine and would suggest paying the $110 to change to a later flight; it is possible to connect in an hour, but wouldn't suggest it on separate tickets

If you miss the flight, then you will likely be on your own

QF won't make a free change since there is no change to that flight

There is no concept of stand by

Since you have separate tickets, make sure that you do have appropriate visa / ETA for Australia , since you may not be permitted to board the flight to Australia if you are ineligible to enter the country