Hai! help me please!

Hiya!
so, here my problem, my little sister (9) has requested i make her a halloween costume (since i know how to sew and stuff)
BUT she is evil, since i had three ideas for her (cosplay >.<)
Yachiru- bleach
Rika- higurashi no naku koro ni
and Rin from vocaliod
she nixed Yachiru-chan and Rika and still needs to see Rin,
and other ideas i can dress her up as besides Loli?
she is short and has shoulder-length brown hair, green eyes and is evil, if that helps, (you dont need to read the spoiler text, its a big rant)and i am demanding payment from her >.<
(i have gotten at least $50 from her just by saying i owed my friends $ (and i did) and she gave it to me, shes rich so i dont feel bad) (wierd little sis, shes also given me money to buy pocky cause i know which borders have strawberry pocky and which dont)

so any ideas that dont involve really fancy stitching?
External Image
so far, she wants this one, Rin, Sakura from Tsubasa, Horo from Spice and Wolf, and idk what else
(sheesh, she has a wide range of choices, but im trying to nix the one in the pic, since it would be hard to make a cat tail, and sakura, since i dont want to style a wig (LAZZZY)

yay! i convinced her to be one of my ocs!
The sketch of isi i put up, as well as a plushie! >.< easy!

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