Cross-breeds are confirmed canonically possible. However, consider that there's no way to represent this in your actual representative avatar. You'd be relying on people examining you, noting your search comment and then acting accordingly.
Generally speaking, you can expect a large number of people you might interact with to just ignore it and treat you like your base species. If that's worth the hassle of having to constantly remind people, and the potential stigma of people just avoiding you (since Au Ra are supposed to be "new" to Eorzea, meaning your parents are also a super rare meeting and romance) then go for it.
Generally speaking, you can expect a large number of people you might interact with to just ignore it and treat you like your base species. If that's worth the hassle of having to constantly remind people, and the potential stigma of people just avoiding you (since Au Ra are supposed to be "new" to Eorzea, meaning your parents are also a super rare meeting and romance) then go for it.