The name of the Wicked Witch, Elphaba, was created by taking the phonetic pronunciation of the original "Wizard of Oz" author L. Frank Baum's initials, L-F-B, which became Elphaba.
It has been reported many times that Idina Menzel wanted to portray Elphaba in this version, but she eventually revealed that she thought she was too old for the role. During an interview with Andy Cohen she said she would happily have a smaller cameo such as Melena, the wicked witch's mother.
Amanda Seyfried was actively pursuing the role of Glinda before Ariana Grande was cast. Seyfried stated in past interviews that she took voice lessons to prepare for her audition. While she was shooting The Dropout (2022), she went back and forth, and auditioned in person several times on the weekends to play Glinda.
Prior to their casting, both Cynthia Erivo and Ariana Grande previously performed in concert events for "Wicked," with Grande performing a song typically sung by Elphaba during A Very Wicked Halloween: Celebrating 15 Years on Broadway (2018), and Erivo performing a song typically sung by Galinda.
The Wicked Witch of the West is not green in L. Frank Baum's original "Oz" novels. She is depicted as an old hag with three pigtails and an eyepatch. The green skin was originally conceived for The Wizard of Oz (1939), from which author Gregory Maguire chose to derive his own literary work. "Wicked" is one of many different adaptations of the "Oz" world that have incorporated the green skin aspect, such as Once Upon a Time (2011) and Oz the Great and Powerful (2013).