What type visa do we need?

We have a flight booked from London-Beijing-Singapore 14/12/2016 -17/12/2016 We would like to take 72 hours free transit and visit Great Wall of China.
From Singapore we cruising to Indonesia,Thailand,Combodia,Vietnam,final stop Hong Kong and we would like to stay for 5days in Hong Kong.Flight from Hong Kong to London stopover in Beijing connection time just 2h45.What type of entry permit do we need?we are Lithuanian citizens.
Thanks