You asked about "Ehneys" from South Carolina.
Not sure if he's a direct relation, but I happen to be working on a history of a Civil War regiment (Hagood's 1st S.C. Volunters), and the unit had a 1st Sgt. by the name of William L. Ehney.
He left the regiment in April 1862 and subsequently joined the 2d S.C. Artillery (enlisting at Orangeburg, S.C.)