Pending H4 EAD with H1B Transfer - Impact?

What happens to a pending H4 EAD (EAD in progress) when the spouse (primary H1 applicant) changes employer?
Can I have new EAD application in parallel when current EAD application is in Progress. Would this affect the current EAD application or timeline?*

Nothing happens. That H4 EAD will be continued to be processed. Yes, you can have another H4 EAD application in parallel with the new employer. But, you will need to withdraw the old one.
You need to discuss with your attorney on the timing and then apply for the same.