"Regarding the Han, after the period of warring states, everybody left alive pretty much looked like the winners ~ the losers having been mostly killed off ~ men, women and children!
Under the Mongols additional ethnic varieties were brought to China for a variety of purposes ~ but until then the Chinese had about as much variation as modern Korean-speaking people."
Again, wrong. "Pretty much look like the winners", you're still operating under the assumptions that there is asingle race called "Han", when all of the anthropologists and history experts will disagree with you. "Han" chinese isa mixture of a ton of different races. Heck, even tody in China there are agbout a thousand different SPOKEN languages (they're called DIALECTS, but really, differen't languges) within the "Han" majority.
What happens after the warring state is Qin Shi Huang decided to unite the language (the written language), because at that time there were several different written languages as well as give a single unified currency, etc. Though the combats were often brutal and cruel, he didn't wipe out the other states, he simply forced them to use the same written language. The same written CHinese today has its roots from his era. Spoken languages still prevailed, though tehre is a common tongue most people in China in various regions still know the local dialect - and believe me, without Putonghua, someone from Sichuan will not be able to communicate withs someone from Hong Kong(Cantonese). So to say that the Han Chinese is a single ethnicity is just ignorant.
And your claim about the Mongols shows you have absolutely no idea what you're talking about -- You probaly didn't realize that in Tang Dynasty there were 300,000 Persians living in China, and Chang-An(Xian toda), the capital, was a true international city consists of Persians/Arabs, Turks, Chinese (Han and others), etc.
It's pretty clear you've never seen one of those tables that detailed the level of carnage during the Period of Warring States. For the most part, all the tribes, ethnicities, nations and communities that did not live in Chin were destroyed.
The people of Chin repopulated the territory. Under the Mongols, in a very, very large empire ~ largest ever in history, many other types of people were brought to or came to China. That's about 1600+ years AFTER the Period of Warring States.
)(Personal note: I take it you're Chinese or of Chinese ancestry and are of the impression that Chinese people don't all look alike ~ it's difficult to convince Occidentals of that.)