Adjustment of Status - I-485

Hi all, I joined immihelp but hardly post. I always read for advice though. I sent in my package April 22nd 2016.
Got text message May 2nd
Got NOA letters in mail May 9th
Got biometrics letter May 13th
Did my biometrics May 26th

Now I got a RFE for a Joint Sponsor, We don't really have anyone to do for us but one of my husband's friend said she will. The issue I have is, she isn't a citizen by birth (yes I know she can still do it). Just that on her naturalization certificate she was married and she got a divorce and revert to her original name. The original name is in her US passport. Can I just use a copy of her passport for her proof of citizenship? (as she cannot find her divorce papers, it was from back in the 60's)

Next question the 125% poverty guideline says $51, 112 for 8 persons, on her 2015 tax return line 22 shows $54,000. Can she cover me with her salary, I'd make the 8th person.
She makes about $57000 per year.

Thanks