FluffyQuack
[14] Master
ARN
Kilik illustrations

Nightmare illustrations

Xianghua illustrations

Kilik screenshots

Nightmare screenshots

Xianghua screenshots

They're definitely based on their SC1 designs, though they sometimes take elements from other games (like Kilik has shoulder armour with an eagle design like in SC4, and Xianghua's hair is closer to SC2 than SC1).
This should be pretty exhaustive:You may wish to pull their SoulCalibur I renditions as well. The observation has been made that the redesigns seem to be a hybrid of their looks between SoulCalibur I and SoulCalibur IV.
Kilik illustrations

Nightmare illustrations

Xianghua illustrations

Kilik screenshots

Nightmare screenshots

Xianghua screenshots

They're definitely based on their SC1 designs, though they sometimes take elements from other games (like Kilik has shoulder armour with an eagle design like in SC4, and Xianghua's hair is closer to SC2 than SC1).