I have gotten statements from the county that my son (22) lives in that there is no marriage recorded for him or my daughter (19). I will appositle them with my Son’s notarized letter from school (stating he is a student) as they are all from California. My Daughter actually lives in NYC right now going to school, but the NYC process is a complete cluster due to COVID. She used to live in that county so I think I will be fine.
Depending on your state/county/local municipality you may or may not have a way to get one of the single status letters. Search for “Letter of No Record / Single Status” and your county or state and see what you get back.
I’m just starting to talk to my Lawyers right now, but I’m trying to get ahead of their requests.