I have always seen OZ as outside the usual Comic universe. And so is able to do their "own thing" so there is a Mystic scene that is as big as can be, but "outsiders" don't get involved. I use the "Dreamtime" as concept of reallity changing mystic power. As for heroes, I just figure they are the same as elsewhere. There are a few comics based in Australia, so Catman is their version of Batman, and is now retired. The Kookaburra is the main Street level hero who works like Jack in the Box from Astro City. I usually assume there is a huge Ninja training ground in the out back. Coil would be a good "Agent" force to use, as they would naturally want to keep VIPER out. VIPER: Japan could be the source of costumed crime war for heroes to deal with.
What are some typical Aussy things that would make good hero themes? I would want to try a char named Digger, with Earth Elemental control, or would that be offensive? I don't know enough.