The Manchus never conquer China, but they do conquer Korea and navally invade Japan.
The resulting thalassocratic Manchu empire colonizes the Philippines.
There's so much wrong in these two sentences that it just seems...so right.
Serious note though, it'll probably be some combination of random sultanates, the Dutch, or Portuguese.
China's had a tendency of having a massive overseas presence due to migrants while also completely ignoring said migrants. So while there almost certainly will be Chinese Han presence (in OTL, there's quite a few Filipinos with Han ancestry), it probably won't be state sponsored (just going by OTL trends).
Japan's even less likely as their main focus has always ever been the mainland, i.e. the Korean peninsula and China. A victorious Toyotomi Japan that conquers AND maintains long term control of the Korean peninsula (which is unlikely seeing how much trouble they had doing the former despite having the element of surprise and more more-experienced troops) will be dedicating most of its resources projecting into China and Manchuria, then also defending from northern nomads, for at least the better part of a century. By which point some European probably has a stake in the Philippines or the Japanese turn their attention to solidifying control of SE Asia (and going bankrupt in the process since that kinda happened with most of the Chinese dynasties at some point, attacking Vietnam and suffering terrible financial losses) or the north. The Southern islands just don't have the same appeal prestige or financially that projecting towards the mainland does, especially for a nation in the Sinosphere, and controlling China as a foreign invader forces quite a bit attention towards bureaucracy (especially if the capital of Toyotomi Japan is not Beijing like with the Jin, Yuan, Ming, and Qing, forcing a shift in management), rebellions, and raids.