(a) Yes. The territories are not as independent as states. But the Australian Capital Territory and the Northern Territory are self-governing as a result of federal legislation (though the federal government has certain overriding powers).
This means that, although there are some important constitutional differences, the governments of the self-governing territories may be treated as the equivalent of state governments.
The territories that are not self-governing are governed directly by the federal government.
Note: Norfolk Island enjoyed limited rights of self-government between 1979 and 2015. However, the Norfolk Island Legislation Amendment Act 2015 (Cth) put an end to self-government and placed Norfolk Island under similar governance arrangements as Australia's other offshore territories.
Click on the links below to see the relevant legislation.