Rooster's Millions, the book being read by Louie the Parrot, is a reference to Brewster's Millions, published in 1902. The original novel tells the story of Montgomery Brewster, a young man who inherits a million dollars (roughly $27 million in 2016 dollars) and then must spend every penny of it within a year, without retaining any assets or property, in order to inherit a greater amount. The novel has been adapted several times, most notably into Zum Teufel mit den Kohlen (1985).
Heathcliffe is likely modeled after Lenny, from 1939's "Of Mice and Men," a lovable, goodhearted, but dimwitted big guy.
Louie sounds a bit like Tweety. Mel Blanc voiced both shorts, so might have been perfecting a bird-like character.