I'm sure someone more learned than myself will come along, but until then, I'd suggest you try reading through the top level comments/discussion on this thread: What popularized names like Shaniqua in African-American culture?

That said, I think your question is more of a sociological one, though it does have historic undertones. As /u/Dubstripsquads mentions in the linked thread, a large part of it is rooted in the Black Power movement, and more broadly, in Afrocentrism. Just as we saw African Americans rejecting "slave name" surnames, a large part of the afrocentric movement is about reclaiming, and in many ways re-inventing, African identity. When I say re-inventing, I'm not suggesting this as a negative.

Think of it this way, if you were Irish, but Irish culture had been almost completely obliterated, and you were taken to another country where the only identity you had was from your owner, and/or the role you performed as a slave, in the absence of a history or a heritage, you may try to create one for yourself.

In the same way, African Americans may not know what tribe/clan they came from, but they do know they came from Africa. Rather than adopting an Anglo-Saxon or other European first name, the trend to create "unique" or different names arose. Sure, it's not a traditional Swahili name, but as your question suggests, these names, whether created or adopted (for example the lesser used first names adopted from French), have been repurposed as traditional African American names. A contributing factor on the French side is that French is the, well, lingua franca of diplomacy, and Africa still has a large French cultural influence left over from colonialism. A related phenomenon is the creation of Kwanzaa as an African holiday alternative.

Some further reading:

• From Booker to Jamal to TeJay: Controversy and the Decline of Conventional and Afrocentric Naming

• Intro to Afrocentrism Apologies in advance for the wikipedia link, if someone has an alternate primer to the topic whose relative objectivity they can vouch for I'd be happy to see it.

• Article on Bias and Afro-Centric Names

• Are Emily and Greg More Employable than Lakisha and Jamal? the study mentioned in the above article.

Hmm…when I clicked on this thread it said there were 10 replies, but I can’t see any of them ;_; Did they all get deleted? Let’s see if I can avoid sharing their fate…

Bluntly stated, OP, many of the ‘unique/invented’ names you describe became popular during the 1960s as part of the Black Power movement. Allow me to quote from Jeffrey Ogbar’s Black Power: Radical Politics and African American Identity:

”African and Muslim names such as Jamal, Jamillah, Kenya, Kenyatta, and Malik are not particularly uncommon for younger African Americans. During the late 1960s, scores of thousands of young parents who were inspired by the tenets of Black Power named their children after kings, queens, and freedom fighters of the African world. Many more, who were not college-educated or without immediate access to books of African names, were likewise inspired by the impulse of self-definition, and Black Power became more creative. For many working-class and poor African Americans, self-definition took shape with the creation of African “sounding” names: Shaniqua, Lashronda, Sheleena, Sharonda, and others.

"These uniquely African American names are not found among those born before Black Power. They are fruits of the era. Though these neo-African names generally connote a particular class background and are sometimes derided, they reflect the fundamental thrust of Black Power: self-determination and a particular celebration of what it means to be a black person in America.”

(1)

There’s no citation for this, but Ogbar’s assessment seems to be backed up by economists such as Steven Levitt. Allow me to quote from his paper:

”Using data that cover every child born in California over a period of four decades, our analysis of first names uncovers a rich set of facts. We first document the stark differences between Black and White name choices in recent years.2 For example, more than 40 percent of the Black girls born in California in recent years received a name that not one of the roughly 100,000 White girls born in California in that year was given.3…mong popular names, racial patterns are pronounced. Names such as DeShawn, Tyrone, Reginald, Shanice, Precious, Kiara, and Deja are quite popular among Blacks, but virtually unheard of for Whites.4 The opposite is true for names like Connor, Cody, Jake, Molly, Emily, Abigail, and Caitlin. Each of those names appears in at least 2,000 cases (between 1989-2000), with less than 2 percent of the recipients Black.5 Overall, Black choices of first names today differ substantially more from Whites than do the names chosen by native-born Hispanics and Asians.

"More surprising, perhaps, is the time series pattern of Black first names. In the 1960s the differences in name choices between Blacks and Whites were relatively small, and factors that predict distinctively Black names in later years (single mothers, racially isolated neighborhoods, etc.) have much lower explanatory power in the 1960s. At that time, Blacks who lived in highly racially segregated neighborhoods adopted names that were almost indistinguishable from Blacks in more integrated neighborhoods and similar to Whites. Within a seven-year period in the early 1970s, however, a profound shift in naming conventions took place, especially among Blacks in racially isolated neighborhoods. The median Black female in a segregated area went from receiving a name that was twice as likely to be given to Blacks as Whites to a name that was more than twenty times as likely to be given to Blacks. Black male names moved in the same direction, but the shift was less pronounced. On the other hand, among a subset of Blacks encompassing about one-fourth of Blacks overall and one half of those in predominantly White neighborhoods, name choices actually became more similar to those of Whites during this same period.

”To justify the patterns in the time series circa 1970 through this model, there must be a shock to the identity prescriptions (i.e., what it means to be Black) around this time period. The rise of Black Power appears to be precisely that sort of shock. The underlying philosophy of the Black Power movement was to en courage Blacks to accentuate and affirm Black culture and fight the claims of Black inferiority [Van Deburg 1992]. Within the Black community, there were widespread changes in hair styles and the rising popularity of afro-centric clothing between 1968 1975 [Van Deburg 1992; Woodward 1974]. The adoption of distinctively Black names would be completely consistent with these other cultural phenomena.

(2: http://www.jstor.org/stable/25098702 )

The sociologists Stanley Lieberson and Kelly S. Mikelson further concur with this analysis. To quote from them:

”Other evidence is consistent with the observation that the contemporary racial differences in the giving of distinctive names is a relatively recent development that reflects a surge in the practice among African Americans. Drawing on 1910 census data for Mississippi, London and Morgan (1994) find little difference between the races in the use of unique names. Mencken (1963:628-29) and Puckett (1975:135) find name innovations were once uncommon among African Americans. To be sure, there is reason to believe that usage of distinctive names was in creasing before the period covered by the Illinois data. Unusual names are more com mon among African American college students from 1910 to 1930 than in the 1880 to 1910 period (Puckett 1938). Puckett also re ports unusual names increasing in comparisons between the pre-1870, 1870-1900, and post-1900 birth cohorts listed in Who's Who in Negro America. However, a study of Afri can American and White college women in the 1931-1932 and 1940-1941 academic years indicates only a small number of either race had unique names (Eagleson and Clifford 1945; for a fuller view, see Lieberson and Bell 1992:547).

”…What accounts for this growth in preference for unique names? The 1960s is a pe riod of broad social and political changes. It is a time of intensified African American so cial protest, an emphasis on Black power, re newed emphasis on a distinctive and valued African American culture, and separatism. Although no distinct event marks the begin ning of this period, the excellent review by Marden, Meyer, and Engel (1992:195-201) lists important events, such as the March on Washington (1963), widespread large-scale riots (1964 through 1967), the organization of the Black Panther Party (1966), the separatist theme among African American activists (1954 through 1968), emphasis on a distinctive African American culture (as in the use of the concept of soul, Afro haircuts, and the study of Swahili in the 1960s), and the development of a call for Black Power (as in Carmichael and Hamilton 1967, as well as in the National Conference held that year).

During the civil rights movement, we saw the rise of Black Identity and the Black Power movement, as well as Islam becoming more common in African American populations and feeding this movement, particularly in large cities in the northeast and midwest. Malcom X, born Malcolm Little, changed his name to X because Little was, as he said, "a white slave-owner's name", and during reconstruction, slaves who had only a first name, took the last names of the slaver who owned them, because not having a last name in the US made you a non-person for all intents and purposes with government agencies. During the rise of Black Identity in the 50s and 60s, there was a movement away from European surnames that had been assigned/taken/borrowed from plantation owners and towards Arabic, Bantu, Zulu, Swahili, and other Afrocentric names.

In Louisiana, there was a large free black and creole population long before the Civil War, and many of them had French surnames and first names, too, as it had been a French territory prior to the Louisiana Purchase. A large number of free blacks with French names moved into the rest of the country in the 100 years after the Civil War, taking their names with them, which also fed this trend away from Anglo/Germanic names.

The WHY is much more complex than this. Here's a great research paper called "Naming and Linguistic Africanisms in African American Culture" from Lupenga Mphande at the Ohio State University on this exact subject.

http://www.lingref.com/cpp/acal/35/paper1301.pdf