What if the Spanish did not colonize the Philippines, assuming that the Spanish instead acquire Mollucas like they planned in OTL?
Would Tondo under the Bolkiah dynasty unite Luzon as an islamic state?
Who would try to conquer the Philippines ITTL would it the French? the Portuguese or the English?
Spanish not colonizing have different outcomes. Being Colonized by Portugal, Dutch or China. Manila and Brunei is given time to recover. Thus, next possible colonization would be around 19th century. The other branch of that story is if Luzon fuses together into one Hindu state. Brunei would be repelled from Luzon instead. Another, Luzon to remain a tributary Chinese state.
Brunei couldn't even make majority of natives of Borneo Islam. The same can go with the Luzon. Islam in the coastal areas, hindu/animism in the rest.
The British or the French can try to conquer Luzon in 19th century especially if Brunei or Manila was able to recover in the 16th century when Manila was just recently conquered by Brunei.
To sum it up, and depending your PoD, Luzon was not assured to become Islam even though it was one of the possibilities.
The other question is would the Visayans(Cebu, Madya-as et. al) be islamised by the Tausugs who had been raiding them for sometime.
Short of military conquest, no way of making Visayas Islam. The Tausugs need to organize a certain degree of invasion and settlement rather than raiding. Like the Vikings, raiding will only increase resistance and defensive capabilities unless you settle on where you raid like the Rus or the Normans.