You can do that makeup look without resorting to MAC over priced cosmetics
Here is how to do the female (and Castors) makeup -
Base - a good primer is essential to create a flawless base. One that says its a satin or moisterising is a good start as itl create a reflective base.
Foundation - pick a foundation with light reflecting qualities, you can add some highlighter to this to create an even more reflective look. dont go overboard as you dont want the skin to be too shiny, even with the Siren's look. you want it to look as if the skin is lit from within. Look for ones with light reflective, irridescent or highlighting in their descriptions. if you want to appear lighter, pick a colour ever so slightly lighter than your own skin tone, do NOT use white.
Concealer Use a creme concealer to remove obvious flaws around the nose, and any pimples.
A different under eye concealer liquid to cover any darkness under the eye and brighten the area. The type like Touche Eclat will help bring out areas you want to give the look of light hitting it - under eyes, top of cheek bones, top of nose, above top lip.
Blusher and Contour - To create the angular cheekbones of both Quorra and Gem, use a taupe blusher to contour under the cheekbones in a c shape and also under the chin. blend in well. You can also apply some highlighter liquid to the top of the cheekbones.
Powder Finish off with a light reflecting powder for Quorra if needed. Sleek do a Powder called the One which has fantastic highlighting shimmer in it. You can add a little extra highlighter powder in white or silver if going for the Siren look. Or you can leave of the powder all together if your skin is dry and the foundation is shimmery enough as is.
Eyes - Quorra had her lids softly defined with black, the lids looked smudged and slightly shiny. A black eyeliner smudged over eye primer and then set with sealant would work well there. a thin smudge line close to the lashes on both top and bottom eyelids and slightly winged upwards, then a thickening and lengthening black mascara to enhance the eyes. White eyeliner on the waterline to make eyes look bigger. A bit of white shimmer eyeshadow on the brow bone.
Jem and Sirens - Strong black eyeshadow in a wing shape. Eyeshadow primer on lids, then a matt nude colour on the crease to browbone. apply a creme or gel black eyeliner over the eyelid to create a good base. using creme or gel means you can get the strong defined cats eye shape. Go over the eyeliner with black eyeshadow with a shimmer. White shimmer applied to browbone. Apply black eyeliner to the waterline. Apply long overly feathery fake eyelashes to both top and bottom lids,. You can get double sets specifically for this doll like look.
Castor apply primer then silver white over crease to browbone. Apply black gel eyeliner over lid and under eye, then apply silver grey powder over that and blend out
Denizens - have block design over their eyes, around foreheads or in tattoo like designs on their face in silver. a good silver pigment directly onto the skin after applying foundation. will create this effect.
Sirens, Castor and many of the programmes have these pale opaque grey/blue/ silver eyes -so contacts would be needed.
Eyebrows -use a black eyebrow pencil to fill in the brows and enhance the arch shape for Sirens and a soft black eyebrow powder on Quorra.
Castor has no eyebrows. Also he has a white stencil design on his forehead. I believe his lashes are also silver - a clear mascara run through lashes then powder gently combed through would give correct look.
Lips - Quorra has defined naked lips. Find the lightest pinky nude pencil and fill in the lips with it, then go over with a clear lip balm or gloss.
For Sirens and Castor, you can use a white shimmer mixed into the balm or a white shimmer gloss.
Companies like Ben Nye, Kryolan, ELF,NYX, GOSH, Inglot, Illamasqua,all do fab products to use, or look in Mineral makeup companies for excellent shimmer powders like Lililolo, Shiro, Fyrinnae, Morgana, EvilShades or Meow Minerals.