One of the well known leaders of the anti federalist was

I think its Patrick Henry.

The leaders name is Patrick Henry.

These all apply to John Locke:

John Locke argued the idea of a "social contract."  According to his view, all individuals possess natural rights, and a government's power to govern comes from the consent of the people themselves -- those who are to be governed.  If the government failed to attend to the rights and welfare of its citizens, citizens then had the authority to unseat that government and establish a new one.    Thus Locke also argued for a government that gave the people a voice in government through elected representatives.

The views of Locke on the social contract) were a change from the previous ideas of "divine right monarchy" -- that a king ruled because God appointed him to be the ruler.  Locke repudiated the views of divine right monarchy in his First Treatise on Civil Government (1690)  In his Second Treatise on Civil Government (1690), Locke argued for the rights of the people to create their own governments according to their own desires and for the sake of protecting their own natural rights to life, liberty, and property.  This included the right to overthrow a government that trampled on their natural rights.

We might clarify a bit about the idea of "individualistic society."  Locke's ideal was one that promoted individual freedom and equal opportunity for all.  Each individual's well-being (life, health, liberty, possessions) should be served by the way government and society are arranged.  In Locke's view, individuals will recognize that they are better off living in a society together than alone as individuals.  So in coming together as a society with a government, they will structure society in a way that protects individuals' rights.