Hi Sue. To answer your questions...
My records indicate your great-grandfather, Samuel II, was born 7 Jan 1845 in McDonaldsville, Stark County, Ohio; his brother Jacob was born circa 1848; and their mother, Elizabeth Graybeal, died in 1856.
I also haven't been able to find Samuel I in the 1850 census.
Samuel I and Mary Rowland were married 20 Dec 1859 in Stark County, Ohio.
My father was told Samuel I was born in Germany (Baden) and was a doctor. I don't know if that information is accurate or if it has been handed down through the family by word-of-mouth as based on the information recorded in the 1880 Census. It does conflict with he 1860 census where "S. Bachtel" (in some records he's recorded as "J. Bachtel"), his wife Mary, their sons, and Mary's children from her marriage to Jacob Goodenberger were living in Jackson Township, Stark County, Ohio. S. Bachtel's occupation was listed as farmer, so I really don't know what he did for a living.
I also have heard the story about Samuel coming to Ohio with brothers and/or half-brothers but can't confirm the information.
If you want to compare other information, feel free to contact me at firstname.lastname@example.org