my goodness !
reading the OP's plans and the subsequent suggestions has given me a headache !!

why alll that dash and possibly slap and tickle .......are we THAT short of time ?
unless we are meeting eg HK and shenzhen or even guangzhou or TYO and OSAKA or BEIJING and Tianjin ..
we need to know if the meeting is THAT important ...which i imagine it is..then at least spend a night in HK ........that would solve everything......i wouldnt like to give an impression to the meeting that you are running short of time....and they can get overtime
get into HK early and i would suggest NOT to time to time everything to that last second cos ........the unexpected always happen.....egg.taxis are difficult at certain times of the day and ..the MTR connecting walkways can be ridiculously long.....
get to HK early and stay overnight in HK .......that my suggestion