Can we get the 144 hour visa

Yes, that's fine. Patterns like A-B-A (where B is Shanghai) are not allowed, but you are doing an A-B-C-A (where C is Shanghai), so all good

The immigration officer reasons like this: Find Shanghai in the pattern of flights and look to the left and to the right of it. The countries to the left and right are not allowed to be China and have to be different to each other

In your case: To the left of the C is B: Hong Kong, which is not being considered in China, and to the right is A: Adelaide, also not in China. Finally B: Hong Kong and A: Adelaide are in different countries. Tick, all good

I just did two trips like that and am very satisfied with how immigration officers at Pudong airport handled my case and how quickly I passed immigration, way faster compared to the normal queues. At Pudong the 144 desks are completely to the left (or right, depending on which terminal you arrive at), at the immigration control area, just after passing the temperature-check gate. While you walk to the left (or right) an officer will come to you and ask you if you are going to apply for a 144 visa as the desks are normally unmanned. He will than call an officer and while you are waiting for him or her, you can fill-in a special arrival card that you'll find there near the 144-desk. When the officer arrives, you have to show your onward ticket (in your case to Adelaide) and your hotel booking confirmation in Shanghai (or anywhere in the Shanghai, Jiangsu and Zhejiang provinces) and you get a small 144-visa sticker in your passport, which states the begin and end date of your '144-hour Visa-free Transit'