What if a Chinese Emperor picks a princess from Tondo as his Empress, the chinese did marry a Korean, she is known as Empress Gi, is this even possible, I think if it does happen Luzon will be known as Jiangguo.
The Ming didn't value royalty from other states in their own marriage relations. However, there were at least two Chinese Emperors whose mothers were non-Chinese people, and in one of those cases, said mother was posthumously honored as empress. It's not unthinkable that a Filipina woman who makes her way to China might become the mother of an Emperor and be posthumously honored that way.
There are similar issues for the Yuan since Yuan Emperors typically married Mongols. Even Empress Qi/Ki should be considered an exception made possible only by the strength of Yuan/Koryŏ ties. It would be even less likely for other countries.
The Chinese didn't really value royal marriages like Europeans do because the emperor has so many women! Also usually the emperor chooses a bride from respectable families, and unfortunately, a princess from "random backwater areas" aren't that respected due to the "Celestial Empire attitude" of the Chinese at that time. The daughter from a line of aristocrats or high-ranking mandarins might be a more sensible choice for the emperor.
Who is Empress Qi/Ki? Can you tell me more about her? Although I don't know her that much, I speculate she doesn't have a high position among the emperor's women. The emperor's favourite concubine might be quite arrogant to her for one.
The Yuan Dynasty isn't really a Chinese Dynasty,the same as the Qing.IIRC(need confirmation),in a proper Chinese Imperial dynasty,a prince with foreign blood generally has no hope of EVER becoming emperor unless he's the only son the emperor has.Empress Ki is a Korean noblewoman who became the Empress of Yuan.