i140 revoked; New h1 transfer

[kumarmk]

Hi I had my i140 approved by employer A on Jan 22 2016. I moved to employer B immediately (stayed with i140 approved employer A for 30 days after approval) after i140 approval and got visa for 3 years (had visa stamping as well). my i140 was withdrawn after 1 year of active period on Jan 26th 2017. Based on the i140 rule update mentioned below, my withdrawn application should have no impact on my priority date and also new employment change. https://www.federalregister.gov/documents/2016/11/18/2016-27540/retention-of-eb-1-eb-2-and-eb-3-immigrant-workers-and-program-improvements-affecting-high-skilled

Now, I have to change to new employer C from Sep 1.

1. Will there be any issue with my new H1B transfer to employer C? reason I am asking is "I did not stay with employer A for 180 days after i140 approval"

2. When my new employer files for GC, can I retain my priority date?

3. If H1B gets rejected for any reason, will I get 60 day grace period to find new employment? or can I apply for i140 EAD (will any critical circumstances apply here?)?

4. if I want to travel to India on emergency when new H1B transfer to company C is in process, and if the current H1 is withdrawn by employer B, can I safely go and come back without visa stamping? or am I eligible for drop box if I should get stamping?

Any suggestions please.