More specific casting details *speculation*

[lanafromoz]

Disclaimer: This is from Wikipedia so take care in actually trusting it...

Principals (in order of appearance)
- Lucy Durack as Glinda
- Anton Berezin as Elphaba's Father
- Melanie Hawkins as Elphaba's Mother
- Johanna Allen as The Midwife
- Amanda Harrison as Elphaba
- Penny McNamee as Nessarose
- Anthony Callea as Boq
- Maggie Kirkpatrick as Madame Morrible
- Rodney Dobson as Doctor Dillamond
- Rob Mills as Fiyero
- Anton Berezin as The Ozian Official
- Rob Guest as The Wonderful Wizard of Oz
- Ryan Sheppard as Chistery

Monkeys, Students, Citizens of the Emerald City, Palace Guards and Other Citizens of Oz: Danial J Brown, Lockhart Brownlie, Anthony Costanzo, Emma Delmenico, Zoe Gertz, Matthew Hamilton, Todd Hampton, Ross Hanaford, Melanie Hawkins, Suzie Mathers, James Maxfield, Deanna O'Leary, Glen Oliver, Ryan Sheppard, Ellen Simpson, James Smith, Michael Snell, Suzzane Steele, Liz Stiles, Christina Tan, Patrice Tipoki, Romina Villafranca.

Standbys and Understudies: Standby for Elphaba - Jemma Stevenson. Standby for Glinda - Erin Hasan. Understudy for Elphaba - Patrice Tipoki. Understudy for Glinda - Liz Stiles. For The Wizard - Anton Berezin. For Madame Morrible - Johanna Allen. For Nessarose - Melanie Hawkins.

"Source". (as much as Wikipedia can be one :P)