How plausible is the Ottomans ruling the Philippines, I am toying that idea for one of my timelines and what will the ottomans get in the Philippines.
Which time period, the 1500s or the 1800s?
The Ottomans in the 1500s were firmly rooted in the west, conqouering Europe was their immidiate priority. To shift Ottoman focus as far as the Philliphines might require some defeats in the Balkans, and earlier Vienna-style last stretch of aggression. It'll have to be immidiatly obvious that the Europeans are too well consolidated to be eaily defeated, or at least you need a stabilization of Ottoman borders with Austria and Poland-Lithuania.
I'd probably go for a mainly peaceful take over of the Philliphines, I can't see the Ottomans easily carrying out a sustained military effort so far away from their homeland given the technological limitations of the period. Perhaps one or more local kings getting Ottoman aid against rivals in exchange for fealty, the establishement for a puppet state, rebellion, succesful Ottoman counter-attack and subsequent total annexations perhaps?
Malacca is muslim already so they don't have a casus belli, perhaps the Ottomans can start conquering the Pagan parts of Indonesia which in OTL converted to Christianity or stayed Pagan before proceeding to the Philippines.Isn't philippines too far. Beside the focus on Europe, If you were in Istanbul, taking malacca is more important than the philippines. There is no value for taking or annexing philippines if your the ottomans in 1500.
Malacca is muslim already so they don't have a casus belli, perhaps the Ottomans can start conquering the Pagan parts of Indonesia which in OTL converted to Christianity or stayed Pagan before proceeding to the Philippines.
Perhaps this requires an earlier conquest of Mesopotamia.