There is no such word as "aboriginals".
While I imagine that indigenous Australians would, perhaps, travel throughout such a federation to undertake education and cultural activities, likely engaging with their first nation co-citizens, and probably advancing causes and claims relevant to those peoples, they would not likely migrate. This is not merely because there are a range of government assistance measures and concessions available in this country, that may not be elsewhere. It is because they don't own the land, the land owns them, and country is fundamental. A concept which now forms part of the common law of Australia, recognised by the High Court in Mabo's case. One of the more complex, but not insurmountable, problems in any federation would be how to balance the special rights of all first nation peoples, from the Maori* to the Inuit, and from the Gadigal people all the way north to .... the Scots.
Perhaps you ought refrain from making assumptions about indigenous Australians and making incorrect statements about them.
[*One of the reasons NZ did not join an Australasian Federation in 1901, was the special rights of the Maori under the Treaty of Waitangi. Another was being beholden to Melbourne for funding. Both of these things would need to be sorted out. In these more enlightened times you would hope the first would be less problematical now.]