For japanese and german colonization, you got to know the relationship between philippines with Germany and Japan which a lot of people in alt history is not aware of. Since everyone assumes germany or Japan will invade the philippines which is a misconception created only by otl 1898 USA propaganda to justify philippine invasion at that time.
You also have to consider who joins the rebels in the philippines. This will let you know the capability of the rebels. Which will define if capable if bringing down spain without any foreign help.
You also must know how much will it cost the japanese or german government to ferry at least 100,000 troops fund and supply for at least 3 years along with a port to unload troops unharrassed. USA did this while they were allies with philippines in manila.
You must also define if this is a surprise attack or the locals will know their will be war with Japan or germany. Usa had the advantage of suprise attack. So if Japan and Germany has no surprise attack, there is a possibility of losing.
As long as the spanish asian navy is intact, Spain will reinforce the philippines just like otl 1897.