The info you have is a correct recitation of what is printed in various books, but arguably incorrect. JB Meullion's daddy was a Cheval. His own marriage records in the Opelousas Church report:

MEUILLON, Jean Baptiste mul. lib. (Francois CHEVAL of St. Charles parish & Marie Anne MEILLON, neg. libre) m. 8 Feb. 1796 Celeste DONATTO quart. libre (Opel. Ch. : Reg. of Blacks, v.1, p. 43)

This is where Hebert got his info. Others see a relationship between Marianne Meullion and Louis Augustin Meullion and the fact that he freed her and assume, wrongly, that he is the father of her child, Jean Baptiste.

If you are really chasing the history of Eloise (Cheval) Meullion, I think you might find the following interesting. On January 21, 1794, JB Meullion purchased 2 mulatto children from Louis Augustin Meullion: a girl named "Eloise", age 8, and her sister (?) Zemise, age 3. This was done in St Charles.

One could, as I do, believe that the "Eloise" is his mulatto daughter Louise Cheval Meullion (Eloise Cheval). We know Louise Cheval Meullion married Joseph Guillory on 4/19/1803. If the child is her, she would be 17 or 18 at the time of marriage (about right for the times). Additionally, the 1796 Opelousas census shows JB Meullion with 2 young (under 15) girls in his household in 1796. Since his children with his wife (Celeste Donato Bello) were not yet born, who are these girls if not the children he went to St Charles to obtain?

In chasing this story, also look at an Isabelle Faceinte (?). I do not know how she fits but JB Meullion "gave" her a house in New Orleans on 1/29/94. Is this an alias for Angelique? I don't know.

Good luck, and you are right. Always question the "facts" printed in someone's book. They may be right, but they may be wrong also.