Tokyo to HKG to PVG to Tokyo???

I would like to go to Shanghai using the 144 hour transit visa. Do I have to stay the night in a hotel or can I just have a layover in Hong Kong? Would it be possible to fly into HKG on one airline with a few hour layover before flying on a different airline into PVG? This trip is all about Shanghai Disneyland and I would like to spend all my time there if possible. Please advise on best itinerary. Thank you.