1. The leader of Jammu and Kashmir, Hari Singh, was a Hindu. When India was granted independence from Britain, initially he sought to keep his independence. He was given the option of which region he wished to join.The majority religion in Pakistan is Muslim. He chose to join with India as the majority religion in that region is also Hindu.
2.While Hari Singh was a Hindu, Jammu and Kashmir were a Muslim majority. Suspecting Singh would choose India, Pakistani tribesman invaded, forcing Singh to call on India for assistance.
With the war over and the economy growing, people were more prepared to raise children.
I don't believe they could have. In order to accomplish what they did, they needed full control of the situation, without fun control, they would not have made things better for their kingdom.
Congress proposed a constitutional amendment but the states did not ratify it.