Some are easy, others aren't... I'm not sure I understand the question, don't you know the name of your son? It's the name you gave him at the bris. For a girl, it is possible that she has no Hebrew name, but not a boy.
Leon -> Leib / Lew -> Yehudah
Bernard -> Ber -> Dov
Irving -> Israel
Sophia is difficult... I would say Sarah, but I can't be sure. There are not always a clear equivalent, like Leon Yehudah. It can be uncommon, like my dad Charles -> Chiel -> Yehiel. Or arbitrary, like me Claire -> Rahel.
Faye is even more difficult, I have no idea.
By the way, why not ask your rabbi / the rabbi your son studies with?
~~ Claire ~~
My ! are Alia, Eidel, Enola, Israel, Dudel, Yuri, Lina, Lorelei, Leilani, Owen, Julian, Glorinda, Mirinda
My ? are Hillel, Meshullam, Johnny, Ginny, Cordelia, Fiammetta, Yocheved
My ~ are Tehila, Tilda, Hailey, Gillian, Huldah
My / are Aglaia and July