Form I-140

My wife's I-140 was approved and I was also on her I-140. My non-profit employer also filed my PERM and is pending with USICS. If I have to switch employers before my I-140 approval and pending 180 days, I am assuming that my new employer would have to file my GC all over again. Given that I was on my wife's I-140, will I be eligible for H1 extensions after my 6yr period if I don't have my own I-140?
Also, can I change employers and my job roles once I have my I-140 approved and pending for 180 days?

I had an approved i140 from employer A for over a year. And my wife has her H4 and EAD approved recently (employer A).
In between, I switched to a new employer B and they have filed her H4 and EAD together with my H1b application. Currently her H4 & EAD is pending from employer B, but my H1b from employer B is approved. my i140 with employer B is not started yet but previous employer i140 was approved for more than 180 days. In this scneario, can the H4EAD approved with my previous employer A's i140 can still be used/valid?

I am with my current Employer since 2008. My GC is filled in EB2 with Aug-2010 Priority Date. Only I-140 is approved so far.<br>
1) Can my employer file me under EB-3 concurrently without affecting my existing EB-2 filling?<br>
2) If yes then what is the procedure for that? Do I have to do my labor and I-140 once again?

My H1 Extension is in progress since Apr 2018. My 240 day work authorization period is expiring on Jan 15th. My employer will put me on Loss of Pay after that. My questions are :<br>

1). If I plan to wait for a decision on H1 extension, will I go out of status after Jan 15th and be staying illegally ?<br>
2). I have approved I140. Can I go back to India and apply H1 extension from there (in case this extn gets rejected), will this be considered cap exempt ?

I had a approved I-140 from Employer-A under EB3 category with PD-Oct’12. My new Employer-B filed for I-140 under EB2 and obtained an approval. However, the PD is Jul’18 even though priority date porting was requested. Employer-A has not revoked the approved I-140. Not sure if this is a typo or default PD on the form with the assumption that I-485 can be applied when EB2 is Oct’12.