I have Agnes Mann b.1742, daughter of Frances Mann Sr. and Elizabeth Page marrying Hezekiah Coleman. I have not done research on Daniel Mann. I have come across a researcher who has Hezekiah MANN b. 1767 Richmond Va. marrying Susannah Martin, 3/12/1795 in Charlotte County, Va. and they have a son John Coleman Mann b.3/26/1806. In the same family you are researching a possibilty.