Addendum to my post. In the book I mentioned, there is a photograph of some of the prisoners at Point Lookout. Several La. troops are identified in the caption:

H.C. Florance, D. Kilpatrick,Van Vinson, F.F.Case, G.W. Depre, L.H. Allan, J. Bozant, C. Rossiter and S.M.E. Clark, all of the Washington Artillery
J. Black of the La. Guards
Edwin Harris of the 7th La.
The caption also states that Kilpatrick became Mayor pro tem of New Orleans, and that Depre was Clerk of the La. Supreme Court