H-1B Extension

H-1B extension was filed on Nov-08-2016 as regular . Visa Expiry on Nov-23-2016 and I-94 on Dec-03-2016. H-1B extension is still pending and on May-16-2017 the case was transferred to another USCIS center. Yet to receive notice on the center. As per 240 day rule, I can work only till July-21-2017.

      I want to know if I have to leave the country on July 21st if USCIS status is still pending? 

Since the case was transferred to another center as of may will I lose priority date of initial filing. Its been already more than 190 days.

I recently had baby born. Can I take FMLA leave will it help me to stay in country?

Lots of questions. Appreciate your help.