He is listed with wife in Chandlerville, Cass Co, Illinois in the 1870, 1880, 1900, 1910 Federal Census roles. Occupation Blacksmith. DOB: Feb. 1840
I could not find a matching listing in the 1850 or 1860 census for him either in Missouri or Illinois. There were a number of Schaaf families in St Louis that listed Baden as their nativity but could find nothig that matched.
I did not find a matching military record for him.
1900 census has him married 23 years to Justina (b sept 1850) That makes his marriage to her in 1877 or therabouts.
1870 census has him married to a Mary born abt 1846 in New York with 2 sons Frank (jr) born 1867/68 and John born 1869.
1880 census has Frank Jr and John listed but he is married to Justina in that listing. There is a 20 y/o Henry Schaaf listed inthe household.
This leads to an immigration listing and ships listing of the William Penn that lists a F. J. Schaaf of Prussia (at the time Baden was part of Prussia). Departure from LeHarve, France and London, England with arrival in New York 26 Jun 1867. Age is listed as 24 (birth abt 1843)
I don't know for sure that the immigration listing is the same fellow in the census listings but the timing matches for him to find his "New York wife" and move on to Illinois.
It might help if I knew his sister's name.
As for the drafting at gun point story, both sides were guilty of it in Missouri during the war but I've not heard of a group selling to the highest bidder. More likely is a broker who would find substitutes for draftees for a price and frankly uneducated poor immigrants were often the sort who accepted the deals. However usually those substitutes were fairly well documented because the draftee wanted to make sure the army knew that person X was there in palce of the draftee.
FWIW
John R.