If he did remarry it could be assumed that they took his word for already being married on the certificate. But I wonder how the IRS handles it, was she employed? I guess your filing jointly, then all of a sudden filing separately, then a couple years later back to filing jointly with someone else...I'm akin to thinking that the Ancestry details were input by a family member after she was identified. Jan-Jun 2006 being the timeframe of their last contact with her/last known alive. She was recovered in 2007. Her family cared.
Her poor son.
I see the husband is remarried - I'd be interested to know if he ever had her declared deceased after she "disappeared". If he did not, that's just one more sign for the authorities that they've got their eyes on the right POI because he knew she'd never come back to call him out for polygamy.
edit: I mean not being already married on the new certificate