Visa Revalidation is for Travel, EAD the basis for your stay in the USA
Try to understand the difference. If your Visa stamp on passport expired, you would not be able to come back without getting restamped for Visa on your passport from a US Consulate outside USA.
Since your I-485 is in process, you would just need to get Advance Parole from TSC (apply using I-131 form) attaching copies of I-485 receipt etc as proof. You can download the form from the web.
EAD is separate. That is for your ability to work.
Hope this helps.