As of 8/13/2015 it has been established via DNA that Warren Harding was definitely the biological father of Nan Britton's daughter, Elizabeth Ann, born in October 1919.
The episode's title, "Hold Me in Paradise" is taken from an erotic poem written by Warren G. Harding to his mistress
In the episode, Nucky volunteers to keep Presidential candidate Harding's mistress and her illegitimate child under wraps with the rest of the mistresses in Atlantic City. In reality, Harding's paramour was ensconced in Asbury Park until the election.
Jimmy said his suit cost $70. That would be $1,039 in 2023.
The campaign song mentioned is called "You're the Man for Us," indeed by Al Jolson.