You found my great-grandfather, who was 2 yrs old when they came to America. That part of Thuringa was in Saxony when they were there.
I have corresponded with the archives in Weimar, and was told by them that what I was looking for would be in Saxony. Weimar had limited information available, but did have the applications for removal from the country and placed Johann's departure between February and May of 1851. He was supposed to leave with his wife, but his daughter, Maria, went instead. Susanna went with Karl/Charles in 1852, probably because Hannah Beta Pauline SEIDEL Ebenstein was pregnant at the time & gave birth on the voyage.
Did you note the last name of Karl's wife? She was from Bachra, and had 2 brothers. They were August & Christoph. Their parents were Johann Michael and Anna Dorthea (Schrock) Seidel. Anna was deceased when Karl & Hannah married in 1849. Johann died in 1877. Any relation???