Excidia: Cree Summer Francks. Cree Summer embodies the sassy attitude I envision Excidia with, and could portray a tempting femme fatale, as seen with her work on TFA as the Hivemother, Blackarachnia.
Crystalia: Charlize Theron. Charlize Theron has an elegant voice, and as her work with Ravenna has shown, she's not unable to do a dark, malevolent queen who'll do whatever it takes to win.
Zenila: Emily Olivia Leah Blunt. Emily Blunt's portrayal of the Ice Queen, Freya, is wonderful. Her voice is sharp, cold, demanding, yet capable of loving, warmth and affection. It is an irony that she would not voice Crystalia, but, still. Emily Blunt could totally rock Zenila's cold, vindictive and spiteful nature, but with an utter adoration for plantlife.
Astrona: Nicki Minaj/Onika Tanya Maraj. Now, Nicki was going to be up here. She's my Home Girl. But I debated on if she would do Excidia or Astrona, as both she and Cree were gonna be on here somewhere. In the end, I decided Nicki's voice seemed just a bit more youthful, and that embodies more of Astrona than Excidia. Nicki can do voice-acting, for she has, see Sugilite for further reference. Nicki can talk fast, such as rapping, and other things, making her a good voice for Astrona, to me.