Hi
@ankushg, thank you for your questions:
I haven't used the keep list of runDceKotlinJs before. I wrote a Gist with the code which is able to find @JsName
https://gist.github.com/Foso/ca126f184378ff2afb98d29f5355ebff
It should be possible to put the keep list in an extra gradle file. From inside the processor you would read the values and then overwrite this gradle file.
For serialization and generated code you could use KotlinPoet or just save a String to a file and save it inside your project folder.