I don't think you were completely incorrect regarding the name of David -- it is, afterall, a name with a debatable meaning. Same as the name Mary (click on the blue link to that one, to check it out).
Interesting that bit of info you found about the David from scriptures having possibly been named after a sun god. There is a belief that the story of Esther is actually an allegorical tale about the goddess Ishtar.
Again, thanks for checking things out with the Academy. Much appreciated! :)