H1B Delayed Change of Status from L1A

[vbakshi]

I am on L1A visa which expires (maxes out) in March 2024. Recently, I got picked up in H1B second lottery. I wanted to understand that can my H1B be filed on Oct 1st as per the process, but can the Change of Status (from L1A to H1B) be delayed till my L1A expires in March 2024? Reason being my wife is on L2S and is working currently. If we move to H1B in Oct 1st and she moved to H4, she will not have employment authorization immediately and hence will lose her job. Please suggest.

Also, how long does it take to get the H4 EAD when filed with H1B on Oct 1st?