L1B to H1B Options

[viskap]

Hi 

 Currently I am in L1B, My Employer is A and working with Client C. current L1b visa expiring on Mar-2022, have one more L1B extension. 
I have got selected in H1b lottery in Employer B . I heard that there are 2 options 

    a)  H1B Filing with Change of Status 
    b)  H1B filling Separately i.e Raise the change status after my H1 Approved. 

Please advise 
     #1) When its likely to hear the update on the H1B filling status ?
  
     #2) On which case, do i need to go back outside US to get stamping ?

         #3 ) If i go by option (a) , with approved H1B and COS,  should i immediately (from next day)move to employer B ?  

         #4) My dependent status would immediately moved to H4 ?  if Option (a) approved with H1B and COS.

    #5) If i take option B,  after H1B approval, With applying the change of status - do i have option to immediately file amendment to change to Client C (Current client) through employer b ?

   #6) Incase of delay to get the H1B Status, do i still have option to apply L1B extension?

Thanks in advance for your advise.