The First National Bank of Stewartsville, Missouri was chartered in November 1889 and lasted beyond the note issuing period.
Andrew J. Culbertson (1840-1919) was President from 1889 to his death in 1919. He was a veteran of the Civil War and practiced medicine in the 1870s to about 1880. Culbertson took up the mercantile trade around that time. He constructed a brick building on the corner of Main Street that would later house the Gantz Bros. store.
Samuel C. Bauer (1856-1933) became President of FNB in 1920 and served until his death.
Joseph Chrisman, Sr. (1836-1891) was the first cashier of the bank. He had previously been cashier at the DeKalb-Clinton Bank.
Benjamin F. Clark (1860-?) served as cashier of this bank from 1891-99. Prior to this, he managed his father's drug store.
John Andrew Deppen (1850-1919) served as Vice-President of the bank. I found a record of this in a 1911 Rand McNally International Bankers Directory. He was also listed as a Vice-President in a different 1917 publication. Deppen's prior work history included post master at Stewartsville and general store proprietor.
Thomas L. King (1828-1907) was listed as a Vice-President at First National in 1895. He was a judge in DeKalb County.
Freeman P. Cornish (1876-1944) served as Cashier from 1900-05
William David Snow (1864-1943) served as Cashier from 1906 until the 1933. His signature as President appears on Series 1929 Type 2 currency issued by the bank. He was Nell Snow's father.
Joel Casper Watson (1846-1924) served as Vice-President of this bank from at least 1917 until his death.
Frank A Gantz (1864-1941) was listed an Assistant Cashier in a 1917 publication. He owned and operated a lumber yard at the time of his death.
Nell Snow (1891-1976) was an Assistant Cashier in 1911 and continuing through 1933. She would eventually become Cashier at the bank. Her signature as an Assistant Cashier appears on a Series 1902 $10. It also appears on Series 1929 Type 2 currency along with her fathers.
I finally noticed that I had a view of the FNB building on an old postcard.

My guess is the following two pictures likely date from 1940-1.

(L to R) Frank A. Gantz, Alfred Fritz Gantz, other 3 unidentified at this time Sources:1.
http://genealogytrails.com/mo/clinton/bios_c.htm2.
Roster of State, District and County Officers of the State of Missouri 1888
3.
The American Bank Reporter: And Attorney List Volume 96 (1917)