If you count southeast Asia as the southern part of east Asia, then the Philippines was the only US colony in east Asia. Guam and the Northern Marianas are in Oceania, not Asia. The fate of the Philippines depends on what keeps the USA from getting it. If the Spanish-American War still happens without the USA making it a territory, then it probably becomes independent, though it may go to the Germans. I doubt the USA would buy the Dutch East Indies. Firstly the Netherlands won't sell it without a fight. I suppose if you manage to get a POTUS sufficiently sympathetic to Venezuela (or create enough political pressure on Teddy) you could get the USA go go to war against the Netherlands in the Dutch-Venezuela Crisis of 1908, but even if the US annexed something, it would most likely be Suriname and/or the islands of the Dutch West Indies. Around the turn of the century, the ideas of the Monroe Doctrine, which originally meant preventing further European colonization of the Americas, and Manifest Destiny, which originally meant stretching from the Atlantic to the Pacific, were expanding and overlapping enough to bring that about. The Philippines were in a good spot for a coaling station, particularly if the USA also got Guam and Hawaii (not annexed as part of the war but annexed the same year although the US-backed coup had been earlier). It's not ASB to make the Dutch East Indies an American colony but I don't think it's likely.