Travel to India when i-485 is still pending with USCIS

[sandeeptripathi]

I came to US on L1-B VISA in May 2015. My wife got her L2 VISA stamped in July 2015 and she traveled to US in August 2015. Her VISA is valid till June 2018.

I had a conversion of status from L1-B to L1-A in January 2016. After that I have not traveled outside US so I do not have a stamped VISA. My L1-A has been approved till December 2017.

Please find our questions below: 
1. My wife is now planning to go on a vacation to India. Does she need to go for VISA stamping before she can come back?
2. We are having a pending i-140 (For me) and i-485 for both me and my wife currently being processed by USCIS. While these cases are pending with USCIS, can she still go and come back as when she is back her i-94 number would change.

For me and my wife i-765 and i-131 are already approved and we got the EAD card as well