Hi there, i a jay ,lebanese living and working in dubai...

we are planning to visit Beijing via Hong Kong..We are travelling Cathay...on our way to Beijing , we will not leave the HK airport..on our way back we will stay for couple of days in HK before returning to the UAE.
-1 DO WE NEED TRANSIT VISA ON OUR WAY TO BEIJING?
-2-CAN WE ENTER HK on our way back? [with a valid visa offcourse?]
-3-do we need a multiple entry visa for 1 & 2?

Kindly advise,
Regards