First, I apologize that I misspelled your last name in my reply. Second, do you have any images associated with the 2nd Louisiana Cavalry (CSA)? If so, I would be interested in learning more (don.gayle@verizon.net).
Relative to the landing of Union troops you mentioned, troops were landed on two significant dates in the fall of 1862. Troops were landed at Donaldsonville on either the 26th or 27th of September and there was a significant skirmish or affair 2-3 miles below Donaldsonville at Cox's (or Koch's) plantation on Sept 27, 1862 (on Bayou Lafourche). On Oct 25 or 26, 1862, a large force under the command of Brigadier General Godfrey Weitzel landed at Donaldsonville. On Oct 27, 1862 they proceeded down Bayou Lafourche and the battle of Labadieville or Georgia's Landing was fought, with the Confederates, commanded by General Mouton, being driven south towards Brashear City.
Thanks
Don