IOTL Le Perouse was scouting Botany Bay the day the First Fleet arrived, so I'd imagine the French may have set up a colony within a few years of 1788.
I have wonder what would have happened if at least some of Australia had been settled by the Spanish. Some of the continent gets settled by the British, more by the French. In the ATL that I have in mind the US removes the Spanish from Aussie just like they did from the Phillipines. Moving forward in time and assuming that is a Pacifc war in WW2, what impact would that have ?