About the Warring Kingdoms Skins (question and Sivir skin idea)

So I love the idea of the Warring Kingdom concept, especially as a huge fan of Dynasty Warriors and the Romance of the Three Kingdoms in general. But I have to ask. Who the hell are Nid and Kat supposed to be from the story? It's pretty obvious that the previous three are modeled after characters from the Dynasty Warriors series (Lu Bu, Xiang Liao, and Guan Yu specifically), but I don't recognize the new ones as anyone in particular. Kat also just doesn't look like she fits in at all. The skin looks Chinese, sure, but it definitely doesn't look very Romance of the Three Kingdoms to me. Nid at least fits the thematic style.

While on the subject of Warring Kingdoms skins, WHY ISN'T SIVIR GETTING A SUN SHANG XIANG SKIN? It would fit perfectly with the weapon + model + theme. I mean just LOOK at this version of her and tell me that isn't just Sivir with two Chakram instead of one.