In keeping with entrenched traditions, the Holston House in The Mansion still has "Negro man waiters," some of whom are the sons of previous generations of waiters (421), and in the ladies dressing room there is "a maid" (422).
In The Mansion this Harvard classmate of Gavin Stevens helps him get a petition to the Governor for Mink's release, and also helps Stevens track Mink down later. (A former Harvard classmate of Gavin, also unnamed, appears in Light in August, but there's no way to know if Faulkner is thinking of the same man here.)
According to The Mansion, male "guests" staying at the Holston House are required to wear "a coat and necktie" in the dining room, while women guests must have their "heads covered" (421). The only guests whom the novel specifically identifies, however, are "drummers" - i.e. traveling salesmen - and they are all men (37).
In a passage in The Mansion that provides a rare glimpse into Stevens' life after he marries the wealthy Melisandre Backus Harriss, the narrator describes his discomfort whenever "guests, even the same guest or guests again," came to dinner (399).
The group of people in The Mansion who admire the new Jaguar in which Linda Snopes Kohl will ride away from Yoknapatawpha consists of "men, boys, a Negro or so" (464); throughout the novel the people of Jefferson are often described as spectators, but the fact that this group explicitly includes blacks as well as whites makes it worth creating as a 'character' in itself.
In The Mansion Mink's lawyer speculates that after Mink gets to the penitentiary, a meddler with "access to the Governor's ear" may be able to secure his early release (50). Almost four decades later, a different Governor approves Mink's petition for freedom (408). (The actual Governors of Mississippi in 1908 and 1946 were, respectively, James Kimble Vardaman and Thomas Lowry Bailey.
The Mansion goes back to the story of the Sartoris twins in World War I and adds a detail to John Sartoris' resume: fighting with the "Royal Flying Corps" in World War I (204), John shot down "three huns" (212) in combat. ("Huns" - usually capitalized - was the derogatory term the Allies used for their German opponents.)
In The Mansion the story of the dead man who was married to the former prostitute in Goodyhay's congregation is told in matter-of-fact terms in a couple pages by Albert, a member of the congregation. Albert says nothing about how he married his wife, but describes how he decided to kill himself during the fighting at the start of the Second World War. He is a Lieutenant in command of an infantry platoon falling back as part of the confused retreat in "Malaya" (a British colony on the Malay Peninsula, 305).