While it may be true that the names in question may have special significance in certain circles, I find it highly doubtful, based on experience and knowledge of human nature, that the parents actually knew or cared what their name choices meant in other languages/religions/cultures. They probably thought they'd invented them. I can possibly see Ugonna being used because it was a common Nigerian name. But I am willing to bet that little ZamZam is not named after any sacred well in the Bible. It would be nice to believe that, I mean, anything is better than believing her name was just picked randomly because it "sounded cute" but chances are the parents do not know the name of the well in the Bible. I know I didn't know its name and I've read the Bible. If anything, ZamZam sounds like a child's nn, like for Zambia, maybe. That would make it similar to a lot of kids' nn's, like Nee-Nee or Boo-Boo or Ki-Ki.
I understand that Dr. Evans is the reigning expert on the meanings and history behind names, and I respect his opinions and judgments very much. However, there is a tendency sometimes in some circles to overanalyze and find significance where little or none exists.
As Freud himself once said "Sometimes a cigar is just a cigar." And sometimes, a silly name is just a silly name.