Ian, I believe that I can provide some sort of a response to your rather broad question, but at the moment I do not have time, and to address the matter adequately would require a lot of words, sufficient words to fill a pretty lengthy paper.
I would suggest a reading of a couple of my articles, the earlier one, "Origin" needs a re-write, but the necessary foundation is still adequate.
http://www.vikingsword.com/ethsword/maisey/index.html
The second article, "Interpretation" I'm still more or less happy with, for as far it goes.
http://www.kerisattosanaji.com/inter...e-keris-page-1
There is another piece of writing I did & that is included in a book:-
https://sunypress.edu/Books/T/The-Cu...sonal-Objects2
my contribution is chapter 6:- "The Journey of the Keris", this piece of writing goes some way towards addressing the Islamic adoption of the keris, but it is far less than is required, I needed to comply with certain requirements.
These three pieces of writing, taken together give a reasonable account of the development of the Javanese keris, & to get to the place where I feel that you wish to be you do need what can be found in this published work.
The question you have asked is really immense, but when I get time I'll have a crack at writing something that might provide some sort of an answer.