TWOV Question

Hello, I am a Canadian citizen and I plan to arrive at PVG on an international flight from Jakarta, Indonesia. I would like to connect to a flight to Hong Kong, and stay a few days in Hong Kong. Then fly back to PVG and stay a few days in Shnaghai, then fly to Japan.

Upon arrival in PVG from Jakarta and connecting to Hong Kong, will I need to visit Chinese immigration and have a visa? I hope to just transit through without visiting immigration and needing an entry permit. Then upon returning to PVG from Hong Kong, I hope to obtain a 72 hour TWOV, as we will just be visiting Shanghai at that point before continuing to Japan.

Thank you.