First of all, don't freak out, you will not be denied even if you don't send everything that they are asking for.
Find whatever evidence you can find and if you come short, get at least 3 strong credible affidavits and you will be fine. The people who are working on these cases are not dumb, they know our situations and I highly doubt that they will deny you because of it. An RFE is not as bad as people are making it seems, at this point it means that your background check is complete and you're on your way to being approved. All you have to do now is to satisfy their concerns. Send them those little evidence that you could find with some affidavits, they are really helpful and they are one of the easiest things to send.