The title of the episode is a nod to "The Lion, The Witch and the Wardrobe", which is part of the Chronicles of Narnia novels by CS Lewis; however, it is not the first in the fictional land's chronology (the first being the Magician's Nephew).
Toad's theme (heard in episode 1.01 "Strategy X", 1.06 "Middleverse" and 3.04 "The Stuff of Villains") now has lyrics. You can hear them during Toad's first fight with Nightcrawler, and at the end when Toad heads back to Wanda (episode 3.07 "The Toad, the Witch and the Wardrobe").