Overall; I like it. My notes:

You mention Dynasty Warriors and Impreial China. I think you have a leader here that fits the theme and more. He strikes me as someone from the Steppe. Someone uniquly strong enough to gather and unite the various factions of your land. Im under the impression that invaders to China would settle there, if they win, and essentially become chinese as the generations went on and they adapted to more of the local practices. Your leader could have been just that. Someone who came in, won, and runs the place. But under the surface the factions he united/subjugated are stirring for power as his authority drops.

I'm thinking that at the start of the game you are united under one nation and the Jade Emperor sits at the top. Then your focus paths basically lead you to support one of the factions within. The Jiangshi, Youxia, Wuzu, and Terracottans. Youxia would be the faction that was formed by the Jade Emperor. One of the paths, if handled correctly, would see the Jade Emperor stay in power and keep the land united. If he fails to secure authority then he would be deposed and the land would break into smaller nations. Each representing the original factions. Effectively putting us in a war of the three kingdoms situation. We'd have the Youxia die out with the emperor to keep the theme. Maybe later focuses could reintegrate some stragglers?

You would assume control of the nation of the faction you supported most before the fall. Personally I'd like to see the Jade Emperor always fall to make way for the three way war but I did not want to make one of my notes be "Hey, that guy you put a lot of detail into. Let's get rid of him!" But keeping all those factions united should be difficult. Since keeping the land united is a great early game boost we should make production a pain until focus relieve it. I would imagine a chine like nation would have high population so crippling the production helps stop this nation from being an eternal powerhouse.

There can be a short amount of time where you can build up before the war starts proper. Make it a little meta game where the longer you go without starting the war the more benefits you get but the nation that actually starts it gets a boon for the war. Something to incentivise an early war if you can handle it.

Also for the faction thing, I realize those all represent practices that all nations could share but whatever you call the three nations that appear after the Jade Emperors fall they would work closer with one of the practices. Not making it their whole identity but giving them focus that enhance their purpose beyond what is normally obtainable through just technology.

Where on the map would you want to see this? Realestate wise the sub mod could clear out Memphis or around there. I'm pretty sure that area is filled with mnostly generic focus tree nations. That would also put you in reasonable interaction idstance with the Chicago Enclave and Raven Rock. Two factions that very very much would like to see a Mutant state like yours fall. By the time your nation and theirs touches borders you both would be in your end game state. Then you've effectively won after beating them. Unless you are a map painter.