For the peak in Sumatra, my guess it is Mt. Toba, an inactive mountain that erupted like 80.000 years ago and trigger Ice Age, CMIIW
It's better with hill.. or hill with oasis?
There is a large lake, Danau Toba, which created from the eruption of that mountain.
German article about Danau Toba
The peak in Java, I identified as Mt. Krakatoa..
Already dead as well, erupted in 1883 and killed >40.000 peoples
Krakatoa
It is actually in reality should be 1 tile west, but it'll create that seems they are connected..
I think it'll be better to changed to grassland.. rather than hill.
I'd suggest a few map changes as well,
1st)
2 peak in Sulawesi should be moved to east, and the grassland moved to west (shift the tiles)
I can't identify both peak right now (in their current location), no idea yet.
2nd)
relocate all Papua 2 tiles east and add 2 vertical islands there, between Papua and Sulawesi, and fill it with Spices.
Both are Maluku and Seram islands, the only place in the world where cloves grew, main target of Srivijaya, Majapahit, Dutch VOC, Portuguese and Spanish.
Okay, I'll get the city name to you tomorrow. I'll create 2 different version, 1 is Sri Vijaya version, and another one is Majapahit version. Most of the important cities stays the same..