Sutpen is the central character in Absalom, Absalom!, which tells the story of his "vast kingly dream" (19). He appears in this novel specifically as the man from whom Major de Spain buys the land on which he builds his hunting camp.
Boon's grandmother was an Indian, "the daughter of of one of old Issetibbeha's Chickasaws" (18), who married a white man. When Boon has been drinking, he sometimes claims she was related to "Issetibbeha himself," which would give him a kind of "royal" pedigree like Sam Fathers, but the narrative treats this claim as specious (18).
"Cousin Louisa" is the woman at the McCaslin-Edmonds place who takes care of Lucius' siblings when his parents go to Bay St. Louis (48). She is probably Zack Edmonds' wife, although the events in the novel take place about half a decade after Zack's unnamed wife dies in childbirth in Go Down, Moses. Louisa may be Zack's sister, but since this sister is not mentioned elsewhere we assume Zack's wife and cousin Louisa are the same character. This novel also refers to "women and children" in describing who lives with Zack and his father, but only Louisa is particularized (25).
Best known to Faulkner's readers as the man who taught Ike McCaslin how to hunt, in The Reivers he is mentioned briefly in the context of General Compson's habit of getting lost in the woods, and identified as "half Negro and half Chickasaw Indian" (20).
General Johnston was one of the South's main commanders throughout the Civil War; after 1863 he had charge of the Department of the West, which included Mississippi. But in The Reivers he is identified as the leader of the Confederate "retreat upon Atlanta" (20).
One of the men who regularly join Major de Spain's hunting parties. He is identified only by the adjective "old" (20). His relationship to Will Legate, who appears in other texts and is also known as a hunter, is not explained.
There are two "McCaslin Edmonds" mentioned in The Reivers. The first is the father of Zachary Edmonds and the Edmonds to whom Ike McCaslin "abdicated the McCaslin plantation" (17). The other is referred to as "Cousin McCaslin (Cousin Zack's uncle)" (118). Both have charge of the plantation in the generation prior to Zack's, and it seems most likely that only one Edmonds is meant. We combine the "father" and the "uncle" into Zack's father, Cass Edmonds. Zack's one definite uncle is Lucius' grandfather, Lucius Priest I.