I don’t think Stanley Anne is the mother.
If I recall properly, this is based on a quibble about whether Stanley Ann ever went by the name "Ann" (Though both Barack's Book and her Aunt Virginia Goeldner indicate that she did) and a vague reference to a wife in the Philippines. Also a reference in that Article in Arkansas that says barry was adopted after his mother died or something.
From my perspective, that is all too weak to hang anything on, and is likewise in conflict with a lot of other known information. The suggestion that people such as Susan Blake, (and that other woman) lying about seeing Stanley Ann with baby in August of 1961, in addition to Virginia Goeldner not knowing who the mother of her nephew was and mistaking her for a dead woman, is just too much of a stretch to be plausible.
Unless I see better evidence to the contrary, I am going to continue operating under the theory that Stanley Ann is indeed the mother, and that either Barack Sr. or Frank Davis is the likely Father.