OP wrote in the original post that the flights are on separate tickets, so any baggage interline is not certain and purely at the discretion of the check in agent. Given that VA is not an alliance partner, nor even a codeshate partner or a carrier which OZ typically does business with, my feeling is that interlining is unlikely.

As for the connection itself, I have done OZ601 several times in J as an Australian and with my non-Australian wife. Pure aircraft to exiting customs times have ranged from 40 mins to 2,5hrs. Any potential flight delays would be on top of this.

The connection is doable but with a certain level of risk and if the OP wants to take the risk then by all means. Me personally I would reduce the risk by taking a later flight.