Yvonne was hired to play the Grey Children by director Christophe Gans specifically because of her small stature and the ability to contort her body. Yvonne was put in a full-bodied suit and was asked to dance in a manner reminiscent of a wounded child. Because the Grey Children are depicted with their faces twisted onto the sides of their heads, Yvonne could barely see out of the suit, and actress Radha Mitchell said that she never saw Yvonne's face, although they shot a long scene together.
- Actress Jodelle Ferland said that Yvonne's Grey Child was the only monster she got to see on the set of Silent Hill.
- To create the illusion of multiple Grey Children, Yvonne's movements were recorded in several different positions and were then overlapped in post-production.
- Yvonne has stated in Making of Silent Hill: Path of Darkness that she has issues with frequent urination, making it so the designers of the costume had to make a flap so she could easily access a restroom without having to take the costume off or bother with any cosmetics.
|Radha Mitchell - Sean Bean - Laurie Holden - Deborah Kara Unger - Kim Coates - Tanya Allen - Alice Krige - Jodelle Ferland|
|Eve Crawford - Nicky Guadagni - Chris Britton - Roberto Campanella - Michael Cota - Yvonne Ng - Lorry Ayers - Emily Lineham|
|Samuel Hadida - Don Carmody - Victor Hadida - Nicolas Boukhrief - Deb LeFaive - Andrew Mason - Akira Yamaoka|
|Christophe Gans - Nicolas Boukhrief - Roger Avary|
|Jeff Danna - Akira Yamaoka|
|Dan Laustsen - Carol Spier - Wendy Partridge - Patrick Tatopoulos - Paul Jones|