There have been a few answers here about the uniqueness common in black American names, but this particular connection seems too coincidental to me. Haiti, New Orleans, and other formerly French areas factor heavily into African-American history, is there any documented sociological or historical connection between that and common sounds in black names today?
You may be interested in this older thread
When and why did "black" names (e.g. Jaquan, Damarius) come into vogue in America? with an answer by /u/raskolnik citing Stanley Lieberson, who’s really the authority on the sociology of names. It only partially addresses your question.
What is the origin of certain naming trends in the African American community? does not address the “La-“ part specifically but particularly /u/Gunlord500‘s comment.
Both of these seem to place these prefixes within a larger post-1960’s trend of unique naming that was particularly prevalent among Black Americans, almost certainly related to a reassessment of Black identity in the wake of the Civil Rights and Black Power movements. Which doesn’t mean they’re not influenced by French (there’s a long French Creole and Black tradition in Louisiana, for instance, as well as French generally signifying sophistication in English language locales), just that none of the previous posters I could related that specific association. I don’t have Lieberson in front of me but I checked Fryer and Levitt and they don’t explicitly mention the French connection (or any sort of origin for these “Black names”). One argument for an explicit French association is that several other French names (André, Chantal, Monique, Antoine, Marcus) also became popular among African-Americans around the same time. However, once these names became established, I remember Lieberson arguing, they frequently changed through morphing and remixing the familiar, so the origin point is not necessarily related to the end point.
I am a linguist, but not a historical one. You might find more success with this question over at r/linguistics. African American Vernacular English (AAVE) has a complex history influenced by many languages. A specialist in AAVE would probably have an answer for you.