Sydney-Shanghai-Auckland

No, unfortunately this is not eligible for 144 or any other visa free transit scheme. The basic rule of 144 and other visa free transit schemes clearly states that the immediate points before and after a mainland Chinese stop have to be in two different countries or eligible territories (eligible territories: Hong Kong, Taiwan and Macau). As you can see your both immediate points are in one territory - Hong Kong.

You can think about adapting your itinerary by taking one of flight segments:

Hong Kong - Shanghai

or

Shanghai - Hong Kong

To be something like Macau to Shanghai or Shanghai to Macau. Since Macau is so close to Hong Kong that would be perfectly doable and in the same time eligible for 144 hour visa free transit.

Thank you. Would I qualify for the 144 TWOV if the itinerary was amended as follows:
Sydney - Shanghai, direct, non-stop flight
Shanghai - Hong Kong - Brisbane

Yes, you definitely would. This is eligible itinerary valid for the wider Shanghai area and you do not need any kind of visa. Have a nice journey.