One last bit of information, after the fact, on Camp Vacherie. Casey indicates the following:

"The strength report of Company A 2nd La. Cavalry regiment shows it to have been at Camp Vacherie on October 5, 1862, but the location is not known. One report gives the name as Camp Vachene."
Casey, Powell A. Encyclopedia of Forts, Posts, Named Camps, and Other Military Installations in Louisiana, 1700-1981. Baton Rouge: Claitor’s Publishing Division, 1983, page 239.

As the 2nd LA Cavalry was still based at Camp Vincent (St Emma and Crescent Plantations, 4 miles below Donaldsonville on Bayou Lafourche) until shortly before the battle of Labadiebville or Georgia Landing (27 Oct 1862) on Bayou Lafourche, it seems probable that Co. A was in the area. Some of the companies had been detailed to locations along the Mississippi River as scouts and to harass shipping on the river. I have documentation that most of Co. E was on detached duty at Bayou Goula (on the Mississippi) NW of Donaldsonville and were pulled back west immediately after the battle on Oct. 27 (Co. E did not participate at Georgia Landing). It seems reasonable that Co. A could have been stationed at Vacherie, LA on the Mississippi for the same sort of detached duty until Oct. 27, and recruited from the locals at that time. Perhaps the LA Adj. Gen.'s archives (Louisiana National Guard Archives) have more information. Unfortunately, we still cannot access the archives (formerly Jackson Barracks Archives) as yet, even though it has been nearly 7 years since Katrina.

Very best

Don