A few thoughts on missing female ancestors. These are not comprehensive and may apply to difficult male ancestors as well.
Never assume your female ancestor did not marry again after her husband died.
The less well-set and younger your female ancestor was when her husband died, the more likely she was to marry again. It’s simple economics and the reality of the time. Even if the widow was older and better set, there’s still a good possibility she married again for a variety of reasons. Her disappearance after her husband’s death may be as simple as her being listed under a new last name.
Your female ancestor appears to have been dropped off by a UFO a few days before her marriage.
There are several reasons someone’s first appearance in a location can be when they marry. They may have moved to a new area for a “fresh start” as a young adult and part of that fresh start included a new spouse. It is also possible that person may not appear in any records even though they have lived in the area for some time. If the time period is such that this ancestor should appear in a census enumeration, consider the possibility that they are listed in the census, but under the last name of a step-father, even if they were never adopted and never actually “used” his last name as their own. The last name they gave for themselves at marriage could have been the name of their actual birth father and, if he died at the right time, they may never have been enumerated with their birth father in any census and may appear in all census records with their step-father’s last name.
Your female ancestor appears to have been picked up by a UFO a few days after husband dies.
If she didn’t marry again (already discussed) consider the possibility that the recently widowed ancestor moved to live with one of her children. The search for a widow after her death should include a comprehensive search in the areas where her children were living when and after her husband died. And don’t forget to search the marriage records. The widow could have found a new spouse when she tired of living with her children.
You Failed to Research the Subsequent Husband Completely.
Information on the non-ancestral husband of your ancestor could be crucial to your research on the actual ancestor. She could have qualified for a military pension based upon the second husband’s service; she may have actually known the second husband before she married her first husband; her second husband could have been related to her first husband; or one of another in a list of less likely, but still informative, scenarios.
Have all the children and grandchildren of the elusive female been fully researched?
There may be a direct statement about the elusive female’s maiden name in a record on her children or grandchildren. It’s also possible a child, grandchild, or even great-grandchild has a middle name that is the unknown maiden name.
Have all the associates of the female ancestor (and her husband) been fully researched?
It is possible that someone who appears as a bondsman, frequent witness, neighbor, etc. is actually a relative of the female ancestor with whom you are having issues? If she is the administratrix or executrix of her husband’s estate, who are the bondsmen on her bond? Associates of your ancestral couple are not aliens who have been dropped off the UFO–they have a connection to your ancestor or their spouse.
Unless your challenging female ancestor was actually dropped off by a UFO. In that case, there may be fellow aliens (literally) who are her relatives and who appear as witnesses and in other legal documents and also appear out of nowhere. You may descend from aliens of the outer space kind and not the “born in a different country kind.”
Those aliens could also explain those unusual DNA results you received too.