Unique and realistic- that's the idea. Of course if you have an Aby than it must be borderline to outlandish extravagant But I would never name them Artaxerxes or so
And I feel you cannot repeat names as they belong to a different personality. In the 18th century it was not unusual to give a kid the name of an older brother or sister who had died- but we would feel different about that now I think.