General Nonimmigrant Visa

1. While I am moving my H-1 New Employer B, What if something goes wrong during H-1 transfer or after that in GC processing with new employer like RFEs etc comes up, can I move back to employer A if employer A is willing to take me back. Does AC 21 portability rule applied to my case also? Since I have not filed I-485 yet, as per my understanding this rule does not apply to me. While my GC is in process with new Employer B and I am in waiting mode for I-140 approval with new employer, What will happen if my time to extend H-1 petition comes up.
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2. Can I still extend my H-1 with new Employer even if I-140 with new employer is in process and not yet approved. Can I use my old Employers approved I-140 to extend my H-1 in this situation.

I was on H1 before completed all 6 years on it and converted to H4 and working on H4 EAD now. With latest court update, USCIS may decide to end H4 EAD program or stop new applications in next few months( we still do not know the final outcome). My EAD expires in November 2018 which leaves me no option of applying renewal before May 2018 ( 180 days clock). If this EAD goes away will I be able to file fresh H1 in April 2019 ? If in next couple of months, my spouse decides to switch Job based on his approved I-140 then my H4 will also need to transfer/extend. At the same time, will I able to extend my EAD at that time or I still have to wait to fall under 180 days expiry clock based on my current November 2018 EAD expiration date.

My question is about switching from an H-1 to F-1 visa. My six years of H-1 expires in March 2018. I have received an offer for a Phd. at Stanford (starting Aug. 2018) that happens to be one of my dream universities. My employer applied for a PERM back in August 2017, it has not been approved yet. Does the filing of PERM interfere with getting an F-1 visa. I know you’ve answered this question in the past regarding an I-140 and I understand that my chances with just a PERM are slightly better ?

Below is my dads background .<br>
Mom has always been a house wife & have lived in India most of her life except for 2 years in 1989 to 1991.
My dad has been working in the Yemen for a subsidiary of American company called Clorex for 10 years as a plant manager for a chemical plant(purely management job). Did an MBA 2 years prior to his retirement at the age of 56 since the company sponsored it as part of employee benefit.Since then he had been living as a retiree , now for 4 years. In between I have took them to Singapore & Malaysia .Have a permanent residence in India .He pays luxury tax for that home. Has a daughter(married and settled in a different town) and a son other than me(works and lives with them in their house) ( I work in the USA on an H1 for past 2 years).Have travel history to Saudi Arabia but not in the past 5 years.
I completely understand its the burden of applicant to prove the non immigrant Intent. But doesn't know how since both the times the officer didn't ask much .Both the times it was a joint interview .Wanted to know your comments.