Is there is a way to get a marriage letter or certificate of non-impediment done in the US? I have learned that no US agency will provide that but ZAGS in Moscow told my fiancé that is can be done in the US with an affidavit before a US consular official. Or if I fill out the appropriate free to marry form and have it notarized, can the notary signature or marriage letter be apostilled? Would that be acceptable by ZAGS?
Instead of such proof of marital status you can submit an affidavit signed before a US consular official in Moscow. Such affidavit can be made and signed only in a US Embassy outside the USA. You can also sign an affidavit before any notary in the USA but it may happen so that such affidavit will not be accepted by ZAGS as a proof of your marital status, while all documents executed at the US Embassy are accepted by ZAGS without any question.