72hr transit visa :BRU>SZX 2 days bus to HKG 8days flight HKG - PEK/BRU with 20h layover

Hello,
i would be interrested to know if the free visa policy applies to this travel plan.
_Travelling for tourism with familly on french and belgian passports
_BRU to SZX - visit shenzhen for 2 days then head to Hongkong by train or bus
_stay in Hong Kong to visit friends for 8 days
_HKG to BRU via PEK. if we have a layover in PEK, can we visit beijing for 48h too?
Would appreciate your response so can book my flights.
Best,
Theo