Backdated H1B approval for amendment - Enter US ? Port of entry?

USA H1B Visa
1

Need an urgent help based on your experience with regards to backdated approval , am on H1b ( no 140) , I’ve received an approval dated 11/30 form an amendment for change in client and location , need your advice

Company : ABC , Client XYZ

Filed an amendment in March 2019 , got an rfe which was responded in September 2019 , case approved on 11/26 , my employer received an approval notice till 11/30

My earlier petition was for same employer ABC but different client AAA which had a approval date of 04/30/2020 with I94 dated of 05/30/2020

In the above case what are my options

  1. Should I leave the country or stay back since my i94 for previous petition is valid till 05/2020?
  2. My employer will initiate an extension process with client XYZ tomorrow which would probably take 10-15 days max for lca + petitions filing , in this case can I be in the state for these 15 days ?
  3. My family is on vacation and their return date is 20 December, can they come back with existing stamping approval valid till 04/2020
    4.my spouse applied for H1b fy2020 ,received a RFE which was responded on 11/24, if I file for my extension now should I be filing her extension based on my petition
2

If the amendment start date is now, the previous approval may not be relevant as you applied for amendment and it is approved. If there is a question at Port of entry on where you work, they cannot say you still work at old company as that is not valid as client changed.
I would suggest you talk to your attorney and make a decision as he knows your case the best.