Although you are talking about FPOC, I have seen enslaved people who were identified by the name of a spouse or parent. The circumstances were different, and when the naming was given by slavemasters we have to be cautious before assuming that the enslaved used the same names among their own friends; but the cases may be analogous, and might suggest a cultural naming practice that crossed the boundary between free and enslaved. Examples I have seen: Ginny Isom, where Ginny was the wife and Isom the husband, or Jim Clarisy, where Jim is Clarisy's son.

For examples of this practice (used by slavemasters and overseers) see the following quote from Frederick Law Olmsted, _A Journey in the Back Country_ (published 1860), page 88:

"The overseer said he generally could call most of the negroes . . . by their names . . . but it was rather difficult to learn them on account of there being so many of the same name, distinguished from each other by a prefix. "There's a Big Jim here, and a Little Jim, and Eliza's Jim, and there's Jim Bob, and Jim Clarisy."

"What's Jim Clarisy? -- How does he get that name?"

"He's Clarisy's child, and Bob is Jim Bob's father."

I have seen rare examples of this practice persist among freedpeople after the general Emancipation, used as the freedperson's legal name; for example George Mike, where George was Mike's son; and William Guilford, where William was Guilford's son.