Is it possible to make Ilocano and Tagalog minority languages in Luzon with at least 500,000 speakers, if the language Tagalog is not even make the minority it would not even be called as Tagalog since Tagalog is the identity of the Kingdom of Tondo which has multiple languages in its core area and one of them are the ancestor of Kapampangan and one is the language of the Kingdom of Kumintang which became called as Tagalog when it assimilated the people north of Pasig river.
If another language such as Kapampangan or Pangasinan becomes the majority language of Luzon - I think there used to be Pangasinan speakers in Nueva Ecija, we could assume that one of them will take up the identity of the Kingdom of Tondo, I just imagine what would happen if both Ilocano and OTL Tagalog become minority languages, would the Luzon secede due to it being more homogeneous?