One should be clear on what an ADIRU actually does.
The air data part does not directly affect flight controls.
The Qantas scenario was cause by the IR part.
3 completely separate and independent ADIRU's and 3 completely separate and independent pitot probes and 6
(3 pairs) of completely and independent static ports.
Under normal circumstances a complete failure of one air data system in flight would be of no significance whatsoever.
Furthermore the air data part is completely independent from the IR part. So losing all air data on one system has no effect on control and stability as far as the flight controls are concerned. In fact you can even switch off the IR part or the Air data part independently.
The reason for it being called an ADIRU is that both independent parts are in the same physical housing.