H1B Extension after 6 Years - I-140 Approved

USA H4 Visa
1

Hi,
I have approved i140 and H1 is valid till Dec 2020. I recently moved to H4-EAD valid till 2022.
I want to take year break from work and stay inside US(I am on H4 now).
A. If I don’t file for H1B extension before it expires, what will happen to my H1B?
B. Can I use that H1B and file for extension somewhere around April 2021 since my i140 is approved?

2

A. Nothing.
B. Yes, as you have I-140 approved, you can use it for future H1B petitions to file them as cap exempt.

3

A. Can any employer file a H1B petitions(after h1b expired, approved i-140) or only my current employer only can file a H1-B petition?
B. And can that H1B petition filed in premium processing?

4

A. Can any employer file a H1B petitions(after h1b expired, approved i-140) or only my current employer only can file a H1-B petition?
B. And can that H1B petition filed in premium processing?