Applying for H4EAD if I change employers?

[bloomingdales]

-->Situation with company A
H1-B expiry: 04-11-2017
PERM approved: July 21, 2016
Priority date: April 21, 2016
Division- EB2
I-140-going on in regular process
--->Situation with company B
I’m likely to get fulltime position here by the end of October, 2016. They are ready to file H 1 transfer and also start GC process if I’m hired. And they are ready to wait until I get my I-140( if I do it premium)
--->My situation:
My husband comes here from on H4 in this November. I started GC so that I can apply H4 EAD soon after his arrival. So my questions are:
1. What are the chances that company A will revoke I-140 if I move to company B?
2. Will my I-140(if approved on premium) be valid if I change to company B? If not can I request company A not to revoke it?
3. If company A accepts not to revoke I-140 can I apply for H4 EAD on this I-140(from company A) and H1 B transfer from company B at the same time(so that I will have a chance to file H4 EAD on premium)
4. How can I get a copy of my I-140 approval if company A is not willing to provide after I get approval?