I doubt that the first mate would pay a cash bribe to take a condemned man from the gallows, or give a durn whether he spoke English if Australia was the destination.
Also, I though Australians were "Prisoners of His/Her Majesty" (hence the derogatory term "pohmmies")...were these Spaniards on an English territory?
The purpose of the journey was to land at The New World with indentured servants grateful to have their lives spared.