With the second part of the question, you could stay at Regal and sleep the night, get up early and take the Airport Express about 8am into HK Station and spend until 12 noon and collect your bags from the Regal to check in or bag drop for your onward flight. Same day ticket on AE means you pay only one way.
There are threads here on FT on HK for 4 hours.
You have more options on your first stopover.