Pakistan is a multicultural country like India. Historically it wasn't a part of Pakistan either. (Pakistan never existed before 1947). Islam is a religion, it is not a native religion of Pakistan, it originated towards the west of Pakistan. Linguistically Koshur is not similar to Urdu, it has a very different style. Geograhically Kashmir is Part of Indian sub continent.
Kashmir, was, is and will remain part of India for the time to come. You lost the best chance in 65. Now it's gone for ever.
Don't jump on any referendum crap. Nobody cares about that since a long time. UN is useless, UNSC is useless, your only option is to take it by force. Looking at your current state, there is no such hope.
If you love the Kashmiri so much, then take them to GB, AJK, or any other place. The land and it's rivers and all other resources belong to India.
And will remain so. LOC will become the border.