I have a question — is it possible we have (2) ann dunhams—a shirley ann dunham and a stanley ann dunham? see link and the +2 next to shirley ann— twin?
http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=REG&db=gen32207&id=I40286
Anything is possible — perhaps S Ann Dunham was in childhood a set of twins living as one identity — the Dunhams alternating which one they kept and which was away at a boarding school in Lebanon or wherever.
maybe you should click on that “Add Post-em” link and ask.