Changing my h1 to h4 using my spouse new employer I797,and applying h4EAD using my spouse I140 from prevous employer

USA H4 Visa
1

Hi I am currently on H1B visa. Planning to change to H4 as my current employer did not find any project and i got approval for a month. My prvious h1B visa is valid till next month.

My I797 approval date is till May 23 2019 but I94 date is May 31 2019. Which date i should consider to stay here. Can i stay till I94 or app date. Please confirm.

I am going to apply for H4 from India based on my husbands I797 approval copy from current employer. Also going to apply for EAD using his I140 from his previous employer.

PERM, I140 process not yet started from his current employer. Wil there will be a impact on my H4 or H4 EAD if there is any issue in my spouse’s new perm or I140 processing from his new employer.(if his perm/I140 gets RFE or rejection).

Thanks for reading my queries. Please advise.TIA.

2

One think I want to point out here: Your understanding of the current I-94 validity date here may not be correct.
There will be an I-94 card at the bottom of your latest I-797 approval, thats what your current I-94 date. Typically this I-94 date must be the same as your I-797 approval date.
Its my guess that your current valid I-94 end date is May 23rd of 2019.