"Mickey's Nightmare" from 1932 is the first Mickey Mouse Cartoon to be distributed by United Artists.
The Orphans first appear in "Mickey's Nightmare" from 1932. They are prototypes of the Orphans, because they are set in a imaginary story, as Mickey's future children.
"Mickey's Nightmare" from 1932 is essentially a remake of the 1927 Oswald The Lucky Rabbit Cartoon "Poor Papa".