When Gavin refers to "John L. Lewis' C.I.O." in The Mansion he is referring to the American labor leader who founded the Congress of Industrial Organizations in 1935 (236).
Born Vladimir Ilyich Ulyanov, Lenin led the Communist revolution against czarist rule in Russia, and was the head of the Soviet Union between 1917 and 1924. Gavin mentions him in The Mansion when he refers to Communist Russia as "Lenin's frankenstein" (259).
In The Mansion Mack Lendon's mother weighs close to two hundred pounds and "liked to cook and eat both" (205). Hence, she probably does not mind taking Tug in.
The deputy sheriff who watches over Montgomery Ward Snopes in The Mansion is named Hunter Killigrew. We assume he is also the unnamed deputy who escorts Mink Snopes from the jail cell to the courthouse at the beginning of the novel.
Hugh Johnson was the head of the National Recovery Administration (NRA), one of the government agencies that Franklin Roosevelt created during the Depression. In The Mansion Charles puts his name on the list of the people "they called communists now" (237).
Hopkins was an American social worker who served in Franklin Roosevelt's cabinet and was one of the President's closest advisors. In The Mansion Charles puts his name on the list of the people "they called communists now" (237).
Hoover was a founder and the first Director of the Federal Bureau of Investigation; he ran the agency from its founding in 1924 until his death in 1972. In The Mansion someone - Gavin is sure it is Flem - calling himself "Patriotic Citizen" sends Hoover a letter warning him about Linda as a "commonist" (269).
The Mansion's cast of characters includes the "last descendants" of Alexander Holston, one of the first white settlers in Yoknapatawpha and the man who established the oldest hotel in Jefferson. These two women are described as "maiden sisters," though the narrator adds, parenthetically, that "one of them, the younger, had been married once but so long ago and so briefly that it no longer counted" (421). They now own the Holston House, and run it with "cold and inflexible indomitability" (421).