An older Dorothy Gale makes an appearance and is played by Teri Reeves. Her younger counterpart was originally played by Matreya Scarrwener.
Dorothy appears in this episode wearing silver slippers, not ruby slippers. The original books had Dorothy wearing silver slippers, but the producers of the movie, The Wizard of Oz (1939) wanted something more flashy for the new color format and changed them to Ruby slippers. MGM still holds the rights to changes to the original story, so ruby slippers couldn't be used.
Hades was the first born child of Cronus and Rhea, but as each child was born their father Cronus swallowed them. Zeus, the last born, was hidden by Rhea and raised to adult godhood. He gave Cronus an emetic which caused each child to be regurgitated in reverse order of being eaten, last in first out. Hades was the last out. Zeus always insisted this made him the oldest and Hades the youngest.
Zelena, the Wicked Witch of the West, learns that her birthday is April 15. Traditionally, in the United States, this is the day when federal and state income taxes are due, making it (arguably) the most unpopular day of the year.
This is the first appearance of Zelena in season 5B after being absent for four consecutive episodes.