The domain ownership restrictions are not much of an issue. But the marketplace is very small.
My personal opinion having tried in .AU is to stick with .COM. Bigger market, bigger sales.
It's easy to get excited in .AU because there are some very appealing domains available to register, but you will quickly realise there are just no buyers.
To answer your initial question outbound is the same as most extensions. Accessing the WHOIS for marketing purposes is forbidden.
But to succeed in outbound you will only be looking at developed websites anyway so you should be able to get in contact via websites.