As well as extensive CGI environments, massive practical sets were built for the film's main settings. Director Jon M. Chu wanted the world of Oz to feel like a real place for the actors and actresses, rather than just a computer-generated background. This included planting 9 million tulips to serve as part of the landscape for Munchkinland, although for wider shots VFX was still used.
The vocals for the ensemble parts were prerecorded by a number of Broadway performers including some alumni from Wicked on Broadway, as opposed to being sung live on set like the lead vocals were.
Stephen Schwartz thought to modernize Galinda's big number, "Popular," by giving it more of a hip-hop style rhythm. Ariana Grande (Glinda) was dead-set against this suggestion, saying, "Absolutely not, don't do it. I want to be Glinda, not Ariana Grande playing Glinda."
The leading duo insisted on singing live during filming. According to director Jon M. Chu, "When we were shooting it, those girls were like, 'F--- the pre-records. We're going live.'" He was initially skeptical of this, since there would be "a lot of wind" in their air pipes as they performed the more complex sequences while maintaining their singing voices. They simply replied, "Yeah. That's what we do."
The horse Fiyero rides in this film is Jack, the horse Jonathan Bailey rode in Bridgerton (2020). Bailey reportedly felt a connection to Jack when making that series, so he asked to ride Jack in this movie.
Stephen Schwartz: Composer and lyricist appears as the gatekeeper who declares, "The Wizard will see you now," at the end of "One Short Day."
Winnie Holzman: Co-screenwriter and original stage book writer, appears in the audience at Wiz-O-Mania as the woman who is excited at the Wizard being able to read the Grimmerie.
Idina Menzel: The original performer of Elphaba in the "Wicked" stage musical in 2003, appears as a Wiz-O-Mania Super Star.
Kristin Chenoweth: The original performer of Glinda in the "Wicked" stage musical in 2003, appears as a Wiz-O-Mania Super Star.