“Saying he was born in Kenya on a literary promotional page for 16 years - mere oversight by editor.”
The birth date is a separate matter from where Barry was born, but alternative narratives must coherently account for both date and place, or try to narrow down the range of both date and place.
Barry, himself, has only hearsay knowledge of where and when he was born and to whom absent an authentic BC, so what Barry has said about his date and place of birth must be backed up by secondary sources.
As you point out, for 16 or so years he had a very public birth narrative associated with his books of having been born in Kenya. There is no comparable consistent alternative birth date given by Barry or his agents that I have seen. Making note of those specific alternative ages and birth years should be done because it might reveal possible motives for having done so.
I'm not a researcher trying to find stuff, I'm just a reader and learner trying to learn. IMHO the way to find the truth is not by trying to make an alternative narrative, but rejecting every single bit of "info" that is not independently verified by non-0bama supporters and/or mere hearsay, rejecting the info on any documents many (non 0bama supporting) investigators say to be forgeries, and starting with a clean slate. Trying to force bits of info - some real, some not, some twisted - into a "narrative" is counter productive. The best way is to find whatever info is out there, sift it through, and whatever is verified, it's a part of the puzzle. The picture or narrative may not be clear for some time. By trying to force info into any narrative is a method that insures failure.
There is no comparable consistent alternative birth date given by Barry or his agents that I have seen.
See above for why "narratives" are useless. People need to look for factual info that relates to any and all characters, peripheral or major, and if the info doesn't "fit" a narrative, get rid of the narrative. Just find info that is not false, and see what picture emerges. Anything else - having a story in mind, and forcing bits of info into the story and rejecting any info as "false" that doesn't fit - bad, bad method.