I am not familiar with neighboring parishes - without a map in front of me, but if you do a search of LA in the 1870 Census, put the letter M in the keyword box using only the last name and you will get several hits for persons listed as only M Young or with a middle initial M or listed as mulatto.

I have done some research for a family in LA who has an Emanuel, and he is always listed as Manuel except on one record. So try E as well.

Denise