小白兔, WorthIT, Radiology and other Experts

I am dealing RFE recently, How risky it would be if I use EAD to work?
If in case I have to appeal for denial, is the EAD effective during that period?

We have never used the EAD, can we renew it?

We filed EAD in VSC, right now we are in NSC area. If we renew EAD, which center should file the renewal?

Appreciate your advice!