One ancestor that I have that was enumerated on a non-population census (in this case, the 1890 Union veterans census) was my great-great-great grandfather Adam Bost. In 1890 he was living in Marion Township, Henry County, Ohio. Below is his snippet from the schedule. He was drafted to Company B, Ohio 38th Infantry Regiment on October 9, 1862 and mustered out on July 27, 1863 at Winchester, Tenn.
52 Ancestors #34 – Non-Population