Thanks Dale! The 14th NY Cav (folded into the 18th NY Cav. in June 1865) may work out: T. Thomas Fortune recalled that the first freedman's school in Marianna was started by a Sergeant Smith and Private Davenport and, according to the rosters at http://www.itd.nps.gov/cwss/, the 14th Cav included such soldiers (I know that this is hardly dispositive since these are not exactly uncommon names). As far as the popularity of the NY unit, I recall - and I'll check my files - that the Marianna Courier or Weekly Floridian taunted Freedmen's Bureua officers Hamilton and Purman by comparing them unfavorably to the Union military officer who preceded them and who was given a sort of going away party in Marianna.
On the same topic, Captain Richard Comba of the U.S. 7th Inf., the officer in charge of the detachment periodically garrisoned in Marianna in 1866-67, had an interesting career in the Nez Perce conflict and retired a Brig. Gen'l.
Congrats on the new book. I plan to order it shortly and look forward to reading it.