Hi. You mentioned Theobald SOEHNLEN. This is the name of my great-great grandfather. However, he was born in 1832. He was in Ohio by 1860 and passed away around 1871.
I don't know for sure who his parents were, which port he emigrated through or exactly which part of Alsace he came from. All of his documents declare he was born in France.
It's a good possibility that any Alsatian named Theobald (or variation thereof) would have come from the vicinity of Thann, since the church there is dedicated to St Theobald.