Thanks to Iovix, who gave me this wonderful suggestion!!

• Bowie
  1. Chris O'Donnell
     
  2. Devon Sawa
     
  3. Matt Damon
     
  4. Leonardo DiCaprio
     
  5. Val Kilmer
     
  6. Mike Myers
     
• Sarah
  1. Meg Ryan
     
  2. Katie Holmes
     
  3. Jennifer Lopez
     
  4. Mira Sorvino
     
  5. Yasmine Bleethe
     
  6. Neve Cambell
     
  7. Uma Thurman
     
  8. Julia Roberts
     
• Kazin
  1. Jay Mohr
     
  2. Christian Slater
     
  3. James van Der Beek
     
  4. Kevin Costner
     
  5. Leonard Nimoy
     
• Jaha
  1. Robin Williams (thanks, Squall Leonheart!)
     
  2. Joe Pesci
     
  3. Danny DiVito
     
  4. Josh Jackson
     
  5. Chris Farley
     
• Slade
  1. Tom Cruise
     
  2. A.J. McLean
     
  3. Chow Yun Fat
     
  4. Adam Sandler
     
• Zynk
  1. Harrison Ford
     
  2. Arnold Schwartzenegger
     
  3. Phil Lamarr
     
  4. Will Smith
     
• Lemon
  
  1. Kurt Russell
     
  2. Dennis Quaid
     
  3. Dolph Lungren
     
  4. George Clooney
     
  5. Nicholas Cage
     
  6. Mel Gibson
     
  7. Harrison Ford
     
  8. Bruce Willis
     
• Zeon
  
  1. Billy Zane
     
  2. Keith David
     
  3. Harrison Ford
     
  4. James Earl Jones
     
• Galam
  
  1. Gene Hackman
     
  2. Jeremy Irons
     
  3. Jack Nickolson
     
  4. Kevin Spacey
     
• Odd Eye
  
  1. Gary Oldman (thanks, WhiteStar333!)
     
  2. Val Kilmer
     
  3. Elijah Wood
     
• Geshp
  
  1. Oliver Platt
     
  2. Jason Alexander
     
  3. Michael Douglas
     
  4. Jon Lovits
     
  5. Brad Pitt
     
• Cameela
  
  1. Sandra Bullock
     
  2. Pamela Anderson
     
  3. Nicole Kidman
     
• Zalbard
  
  1. Tim Curry (thanks, H Hog!)
     
  2. Dennis Quaid
     
  3. Leonard Nimoy
     
• Astral
  
  1. Sean Connery
     
  2. Michael Ironside
     
  3. Morgan Freeman
     
• Elis
  
  1. Michelle Pfeifer
     
  2. Sarah Michelle Gellar
     
  3. Drew Barrymore
     
• King Granseal
  
  1. Pete Postlehwate
     
  2. Mickey Rooney
     
• Mitula
  
  1. Pita Wilson
     
  2. Vanessa Marcil
     
  3. Winona Ryder
     
• Creed
  
  1. Tommy Lee Jones
     
  2. Lance Henrikson
     
  3. Billy Crystal
     
• Peter
  
  1. Leo Di Caprio as voice (thanks, H Hog!)
     
  2. Matthew Perry
     
• Volcanon
  
  1. Frank Langella
     
• Chester
  
  1. Stephen Fry (thanks, H Hog!)
     
  2. Rider Strong
     
• Luke
  
  1. Aidan Quinn
     
• Gerhalt
  
  1. Kevin Sorbo
     
• May
  
  1. Danielle Fischel
     
• Rohde
  
  1. Robin Williams
     
• Eric
  
  1. Charlie O'Connell