From What I heard the Conquest/Purchase of Tondo and its subordinates to Spain is one of the reasons why Japan is pushed into Sakoku, I am thinking if Tondo and its subordinates convert to Islam voluntarily, the native aristocracy there will retain their status and Luzon will be will as or more unconquerable than Mindanao and Japan would be less alarmed and they will be more or less complacent of what is happening around but the consequence is that Japan would be encountering Islam earlier.