Interesting as always, Andy, and very well reasoned. Thanks!
Is it possible that naming a child something with negative connotations might have been intended to ward off bad luck or jealous spirits or something? Caleb could have worked well, if so - the public meaning of 'dog' in the modern Levant is pretty negative to this day, and might be the first to spring to mind of gullible supernatural entities, while the family could secretly retain the private meaning of, I don't know, loyal, affectionate, helpful ... good meanings.
In a similar way, histories of English surnames tend to go on about how tall people would be known as Long, good singers as Nightingale, dark-haired ones as Black or Brown etc; knowing the English as I do, I'd expect the first Longs to be short, Nightingales to be tone deaf and albinos to be jokingly Blackened. Might have been the case as well with at least some little Calebs!