I have an approved I797 from OCT 1st 2017 to SEP 30th 2018 with Employer A. Employer A's company is merged into Employer B's company from Jan 1st 2018, and I have been under Employer B's payroll since then. I have recently applied for H1B extension with employer B's company and I have an approved I797 for the period of OCT 1st 2018 to Sep 23rd 2021.
Am traveling to India in Aug and plan to travel back around Sep 15th after getting my visa stamped (Am eligible for dropbox). I am going to add both the I797 receipts on my DS 160, but visa appointment application accepts only 1 I797 receipt for which I plan to put the recent one with Employer B.
What dates can I expect on my H1B visa once I am stamped?
What if I get stamped for OCT 1st 2018 to Sep 2021, can I enter US on sep 15th with both the I797 approval notice and some documents to prove the Employer A and Employer B merger?