Hindu Vahini is not a bad idea but without a certain objective, it will backfire. The objective of any resistance should be territory under our control or at least with great autonomy. NE faction has been quite successful in making GoI yield. GoI treats those treaties very sacrosanct. Hindus must attempt such resistance in Bangladesh. Not to mention Tamils failed miserably in Sri Lanka. Kashmiris have been very successful as their objective was dictated by Pakistan who feared a military conflict with India after the 1971 defeat. They got more than what they wanted and inflicted heavy losses on Hindus. Now their pimps are back in power again.
I mean there are a lot of examples and we can try the best of the lessons to create a buffer state.
It would be highly foolish of the Indian establishment if there is any to live beside a highly illiterate and radicalised Islamic state that can infiltrate into our states without much resistance. It would not take them much time to use this infiltration as a strategic strike package posing military implications.
Having said all this I spoke about resistance backfiring. It is because we do not know how Jihadis of Bangladesh will react and I do not want to deliberate on the options they have. Assuming they will act like dodos of the GoI establishment who have been not able to even see the kind of pattern insurgencies in India are following and the trick they employing it will be easier to negotiate. But it seems unlikely. Small nations do act with this magnanimity like Hindu fools do.