I just had to bring this topic back into daylight!
Since I'm used to the German version, I always thought his name was "Fye de Flourite" and I have to say I like it best because it just sounds so elegant, blue, pretty and curvy. So I never thought about the D. But if CLAMP spells it "Fay D. Flourite" in the official book, there has to be something about his second name. Well, what could it be? I personally am not a big fan of Russia-Fye. I always thought of him as somewhat French, not only because of his name.
But "Dietrich" is a funny idea
Though I don't think it fits him so much. What about "Detlef"? It's a terrible name, but it's just
the gay name
So, I still am thinking about nice European names *thiiiinks* maybe there's something cute here in Germany that doesn't sound too German, though...
I once knew a boy who's name was Dino, how about that? Fye Dino Flourite?
By the way, I found a German page for rare boy's names. There were some nice ones: Dion, Darian, Devin, for example.