Everything you say makes sense. I didn’t think the concrete name plus or minus “king” meant much of anything, just brought up my little snip of memory “for the record”.
The claims of being Indonesian royalty seem definitely connected to the Soebarkah name and plans in Indonesia for him.
I still would bet a lot of money (if I gambled and someone would take the bet, and we could ascertain the truth) that Zero speaks Bahasa fluently.
It would be good to have a “concrete name” for this guy!