H4 through spouse and my H1 petition approved one after other. What is my current status

[Am4h1]

I am currently working under H1B. My employer filed an amendment petition and was in progress.. I decided to change to H4 status and my spouse applied in Mar 25th for H1 to H4 Change of status with effective date as future date- May 20(so that i can provide enough notice period to my employer and get my pending h1 approved before H4 COS effective date). My employer upgraded my h1 petiton to premium within 2 days. 
On April 5th h4 COS approved and on April 10th we received approved petition and came to know COS was approved immediate effective date ie. April 5th.. On April 13 my H1B got approved.. 
Further my attorney requested USCIS for an updated COS petition with effective date as may 20th and informed me to continue work in H1B. I am not sure when will i get updated petition.. 
1. Since h1 is approved after, H4 COS approval, am i back to H1 status as per Last action rule?

2. what would be my status after may 20? Should i stop working from May 20th even  if i don't get updated petition approval from USCIS.. 
3. How long would USCIS approximately takes to respond? Once i get updated petition for COS to H4 with specific date,  how long will be grace period to stop working?

4. Is there possibility for USCIS to stick with effective date as April 5 only for h4 COS ? if yes, will i continue to be in H1 status? if yes, should i file new H4 COS petition again?

[shekar11#]

On 5/7/2017 at 9:00 PM, Am4h1 said:

I am currently working under H1B. My employer filed an amendment petition and was in progress.. I decided to change to H4 status and my spouse applied in Mar 25th for H1 to H4 Change of status with effective date as future date- May 20(so that i can provide enough notice period to my employer and get my pending h1 approved before H4 COS effective date). My employer upgraded my h1 petiton to premium within 2 days. 
On April 5th h4 COS approved and on April 10th we received approved petition and came to know COS was approved immediate effective date ie. April 5th.. On April 13 my H1B got approved.. 
Further my attorney requested USCIS for an updated COS petition with effective date as may 20th and informed me to continue work in H1B. I am not sure when will i get updated petition.. 
1. Since h1 is approved after, H4 COS approval, am i back to H1 status as per Last action rule?

2. what would be my status after may 20? Should i stop working from May 20th even  if i don't get updated petition approval from USCIS.. 
3. How long would USCIS approximately takes to respond? Once i get updated petition for COS to H4 with specific date,  how long will be grace period to stop working?

4. Is there possibility for USCIS to stick with effective date as April 5 only for h4 COS ? if yes, will i continue to be in H1 status? if yes, should i file new H4 COS petition again?

Best thing is to file for H-4 COS again. USCIS does not consider the future effective date even if we fill that date in the form.