Got it solved myself. Sharing the solution if anyone else got similar issue.
Monaca LocalKit upload does not sync well. It does upload all files and online IDE does show all files are there. But some connection is missing with Monaca Build service.
I uploaded all Files manually with folder structure inside www folder using Monaca web IDE.
Steps:
1) Open Monaca Web IDE, right click on "www" folder and select Upload option, upload window will open which say "drag and drop files here"..
2) In file Explorer, select all files and folder inside "www" of my localKit project, drag and drop it on Monaca Web IDE upload window.
3) After Upload completes, Now try Build for android and this time, APK file will bundle all missing resource in 'www' and on installing on phone, it will work perfectly fine.
I hope this will save someone a day until Monaca fixes its localkit upload/sync issue.
Thanks