H4 In Progress, H4 EAD yet to apply

I have applied H4 extension for my spouse and didn’t apply the H4-EAD yet. We are planning to travel India next month and will be back after a month.
My Query-

  1. Since we are getting a new I94 - does it impact the current EAD which is valid till Dec’2022.

  2. Once I return from India, I am planning to apply for her H4-EAD extension, if H4 is in progress (pending) - does it cause any issues?

  3. Can she continue work in H4-EAD, with those 540 days rule?

  4. If the H4 is in Pending, until I enter USA - will the H4 process goes abandoned status?