OR, ser 1, Vol VI, page 595:
Question. What was the number and composition of the troops in the city at the time of the evacuation and how were they armed?
Answer. There were two brigades of State troops, under Generals Tracy and Buisson, in New Orleans at the time of its evacuation. These numbered in all, perhaps, 8,000 men; were new levies, chiefly composed of the men of the families resident in and about the city. They were indifferently armed, shot-guns being I believe the prevailing weapon. Two-thirds of them belonged to the French class of the population. Included in the above estimate was a battalion of some 400 men, Orleans Guards, which was well armed and equipped. There were, besides, the Confederate Regiment State Troops, about 700 strong, well armed and equipped, and the Pinckney Battalion (now Eighth Louisiana Battalion), heavy artillery, 500 unarmed men, newly enlisted, occupying the works on the river above and below the city; also the Thomas Battalion Confederate Troops, numbering about 350 men, also unarmed.
The Louisiana Native Guards wouldn't have been part of the European Brigade, and it's not mentioned among organizations of the other brigade. Earlier testimony in your post about General Lewis specifically mentioned the LNG, Lewis stating that it was not requisitioned. If the directive from Governor Moore cited by U.S. General Benjamin Butler is accurate, it may be that former officers of the LNG called their men into service, citing the emergency created when Farragut's fleet passed Forts St Philip and Jackson. Based on months, perhaps years of militia training, these men may have peformed admirable service as provost guards.
General Lewis clearly states that the LNG was never requisitioned by Governor Moore. Officially the LNG didn't exist. However, based on the publication issued by Governor Moore (which reads more like a pleas for help than an order), members may have come out spontaneously during the chaos in the streets as described in the Parton account.
This seems reasonable given the evidence produced this far.