Despite of not being my favourite Xiaoyu's classic costume, many people love it. So I made it to finish the Tekken 3 Costumes Set.
C_XIA_TEKKEN3_2P_P.pak: - The mod itself. Select Preset 1 (Magica Set) in Character Select Screen.
C_XIA_TEKKEN3_2P_CUSTOM_P.pak (optional): - This file enables the mod via Customization Mode. Select Disheveled Hairstyle, T-Shirt (Standing-Don) (Upper Body) and Leather Pants (Lower Body).
C_XIA_TEKKEN3_2P_PANEL_P.pak (optional): - Character Panel: Shunya Yamashita (big thanks to Angel_of_Darkness from Modding Zaibatsu Discord Server for making the render edit)
My Tekken 3 Xiaoyu Default Costume mod here: tekkenmods.com/mod/117/tekken-3-xiaoyu-1p-costume
Also, check her Classic School Uniform mod made by Soup: www.deviantart.com/soupforsiuts/art/Xiaoyu-School-Uniform-844665804