USCIS service center where your I-485 is pending,ask to
switch your I-485 on EB to try to avoid I-485 is denied
if NIW application is denied after responding RFE,I think you will have a safe period to use AP within at least 30 days since you send out RFE even NIW is denied after you respond RFE,you may leave & come back to USA with AP during the period.