Dear Herman,
Unfortunately I could find no more information than what was posted on the PM's website:
This only says: "In the meantime, proposal from Bihar, Assam, West Bengal was also received for conferring status of Classical Language to Pali, Prakrit, Assamese and Bengali."
I do not think we will ever see the proposal(s). But I would be very surprised if international actors were involved in any capacity other than providing support or evidence for the proposals (which, this announcement leads me to believe, need to be submitted by a state government).
Andrew