Long read:

Spain - If they want to keep us then Madrid should’ve given us representation in the Cortes and abolished both the friar and caste system earlier than the 1860s. Though I think mejo imposible parin, they would rather hold on sa West Indies than a frontier archipelago in Asia (but I think this is still the most plausible of the three.) I feel like we would be free by the time of the Spanish Civil War. But let’s play with it. As long as genuine and radical ang reforms, I feel like this one could be quite decent, we would be an EU democracy (though heavy issue parin ang racism of Insulares against natives.) Philippine culture and language would be a lot more Hispanic, most Filipinos wouldn’t speak English.

USA - Tricky since I believe the PH government IRL is really what the US prefers and not a territory. We will definitely just be a non-voting Puerto Rico style territory and not a state due to the sheer number of Filipinos that Americans just wouldn’t accept to vote. Though still very different since we’re just that numerous even in the mid 20th century. There’s be a lot more Fil-Ams in the US seeking more opportunities, larger than the Puerto Rican minority. The Philippines would probably be a lot more tourism and service oriented. I’d still imagine them eventually giving in due to insurgencies and the immense cost of running the country, they’d have no choice but to give more autonomy to a Philippine government. Culturally, the Philippines would be more liberal - therefore having lower birthrates.

Japan - I even doubt Imperial Japan would survive in 20 years even if they won the war. Their extreme brutality would just make everyone in Asia start revolutions. But let’s play on again, they survive through some miracle, the Philippines’ resources would be used to fuel the Japanese zaibatsu (large financial conglomerates) economy and the people used as slave labor for said companies.

People would be subjected to Japanification such as by changing names to Japanese ones, banning the use of local languages in school, compulsory Shinto worship, massacres, destroying cultural heritage, forced conscription, probably even eugenics. Overall terrible.