WI: The Philippines had adopted guns or gun-like technology much earlier?

I suspect that the san yan chong might be the most common gunpowder weapon of the Ming Dynasty. Even without the gunpowder weaponry, the lands of what became the Philippines still managed to resist European colonization, mainly because of their familiarity with various gunpowder weapons that they didn't shake and run away from Spanish muskets and cannons. The warriors led by Lapu Lapu had iron weapons, which was in contrast to the Mesoamerican civilizations that may not have any access to iron.

Only thing is, the lone source of gunpowder technology in all of Asia was the Ming, so if the lands of what is now the Philippines resisted European colonization, it would remain divided between the Bruneians (which controlled the area of what is now Manila), southern Palawan, and has certain amount of control over the Sulu Sultanate, and the Ming itself (Caboloan and Ma-i would be tributary states). Over time, it would become more contested between the Ming and other newcomers.

Although I could also see parts of Luzon other than Pangasinan become a pirate kingdom. Aparri, from what I read up in its origins, was a Japanese trading post, so perhaps an ambitious Japanese pirate sets up a Wokou kingdom in what is essentially northeastern Luzon.

However, the search for the Spice Islands wouldn't stop various European powers from trying their luck at colonizing the lands of what became the Philippines. Keep in mind that absent of any European colonization of OTL Philippines may also result in a Muslim majority population of that region, or somehow Buddhism becomes a major religion there, depending on whichever Asian power colonizes it.

Back then, the lands that became the Philippines consisted of several small states, though I'm not sure if they were allied to each other or not. The Ming were developing their gunpowder tech, but I also agree that the MidEast and Central Asia were also developing their own gunpowder technology. The Ottomans are a prime example of this.

As for the conquest, I suspect that if another European power would come knocking, the states that were not Muslim might end up allying with them against the local Islamic powers.

The trouble is that we hardly have any records that detailed the histories of the pre-Hispanic states in what is now OTL Philippines, aside from hardly understandable history of certain states like Maynila, Tondo, Selurong, and others. Also, OTL Philippines is sitting at the heart of the Pacific maritime trade, meaning that we’d engage in trade with China, Japan, the other kingdoms of SE Asia, and so on. That geographic position is the main reason why we’d fall to the inevitable European colonization. And would it be in the interest of the Ming to share their gunpowder technology with their vassals? Central Asia and the Middle East are long ways from the Philippines.

Exactly, that means they can buy firearms from China,