I am familiar with Wells road which runs south of Namozine. A map of Amelia in The Official Military Atlas of the Civil War shows that several Allen families and Colemans lived along this road. (Wells Road was part of the route in "Lee's Retreat" where a group of New York infantry broke into Richelieu and Cornelia Coleman's house, stealing, among other things, the family bible, later to be used by the Cole family of New York) I have been unable to find the Manns on this map.
While Ancestry.com's census summary (when searching by name) shows a Robert W. Mann in the Mannboro part of the county in 1860, it seems that their Amelia census records end prematurely. Not only are the Manns missing from available census pages provided online, but many of the Colemans in Mannboro, including Richelieu (who should have been there), as well.
It would be interesting to know how all of these Amelia families were related during this time period. I do not have records on your Colemans, but will keep them in mind as I continue my research.