New H1B Petition Filling & Related to i94 expired

I am on h4 visa status and My i94 was expired on February 2020.
My husband’s H1b and my h4 extension was filed before i94 expiry and we are waiting for approvals.
I had done with my h4 biometrics on February 2020.

I got selected in lottery this year.
My understanding is the employer will file COS H4 to H1B while filling petition.

my questions are.

  1. If h1b gets approval after h4 approved , should I be fine to join work
  2. If h4 gets approval after h1b approved , should I file COS again from h4 to h1b
  3. Can we withdraw on-going h4 extension with USCIS once h1b gets approved. In this case , will I incur unlawful status (i94 already expired)

I would be grateful for your comments and suggestions. Thank you.