I believe I have some information that might be useful.My father was Raphael Iungerich, who was the son of Eldred Edward Iungerich. Stevan Iungerich (your Steven Sr), was from Eldred's first family.Raphael was from Eldred's second wife, Florence Kintner.
Stevan's sister is Nadeshda (Nadia) Iungerich (Mrs. Thomas Williams) whom I still refer to as Aunt Nadia.She just turned 90 last November and lives in Pigeon Cove, MA.She is the only living child of Eldred Edward Iungerich (1876-1947).
Eldred was my grandfather and I have alot of information about him through Nadia.
Eldred's father was Edward Coleman Iungerich (1829-1907). His mother was Regina Hanau.
Edward Coleman's father was Louis Christian Iungerich (1803-1882). Louis emigrated to Pennsylvania with his father, Michael Iungerich (originally spelled Jungerich)in 1821.
The surname seems to have branched off of Guengerich, Gingerich whose origins are in Berne, Switzerland.
I hope this is helpful.I was born March 19, 1967.
I also know your grandfather Stevan married Fanny Lechner (1911-1955).