H4 Status with H1B Transfers - Withdraw or revoke by old employer?

My H1B extension got approved recently with Employer A and my dependants H4 extension is pending due to recent i539 changes. My H1B transfer for Employer B got approved also and H4 extension is still pending for the same. I would like to know if I moved to Employer B and my Employer A revokes H1 with them will it affect the status of my dependants?

It will NOT affect their status. Their H4 status is tied to your H1B status. As long as your H1B is in process or approved and you are maintaining status, they are fine. Also, as they have a pending H4 applications with USCIS based on your current approved H1B, you are fine.