What are common Hebrew or Yiddish names for the English name Louis? Would this be Loeb or Levi or others?
YMMV, but the Previous Lubavitcher Rebbe wrote that there was a "Pierre Louis" (an assimilated Jew from France) who visited Harki. The town was Chassidic, and it happened that one of the townsmen visited the Baal Shem Tov in the interim.
The Baal Shem Tov then instructed Rabbi Nissan to go to Pierre Louis and tell him that he was of Jewish descent; that his name was really Pesach Tzvi, after his mother's grandfather; "Pierre" being the French name for ''Pesach," and "Louis" for "Levi," for he was a Levi.