You are correct. Actually, Hilaire had siblings from two different fathers and two different mothers. Hilaire's parents were Antoine Lux and Marie Anne Muhlheisser from Schirrhein. They also had Georges, Laurent, Ambroise,and Albaie. Antoine had another child, Catherine, from his first marriage to Barbe Linck. Marie Anne married Joseph Pfefferkorn after Antoine Lux died.
Hilaire's half-brother Jean Pfefferkorn is my great grandfather. He also had a half-sister Marguerite Pfefferkorn whose son Albert Engel later became a U.S. Representative in Congress from Michigan. Other half-siblings were Caroline, Marie Anne and Madeliene Pfefferkorn. Most of these children first settled in Massilon, Ohio but some moved to Indiana and Missouri.Caroline Pfefferkorn married Michel Schitter and lived in Strasbourg, France. Her daughter Catherine died in Strasbourg in 1949. This family had a lot of braches on it.