The one thing we know he's not is an American citizen, since he was born in Mombassa.
wicked!
I tend to think he was actually born in Vancouver in late August, not Kenya or Hawaii in early August. Transoceanic air travel for a VERY pregnant Stanley Ann or a newborn Barry would have been quite problematic -- thus leaving me with the thought that Mom went back to Seattle, her pre-Hawaii home, earlier in her pregnancy and ended up (for whatever reason) having the baby in Vancouver. Grandma then realized that her child wouldn't have an American birth certificate and filed for the COLB in Hawaii.
The other piece that seems to fit with the late August Canadian birth is the well-documented interview with Stanley Ann's friend (can't remember the name) who said that in late August/early September (again, I can't remember off the top of my head, but it's been documented) that Stanley Ann had a new baby and basically didn't know how to change his diaper. What single mom wouldn't have diapering figured out by the time their baby is a month old? They'd have changed dozens by then.