how did Locke,Montesquieu,Voltaire and Rousseau influenced the American Declaration of Independence?

You seem to have the basic ideas correct about Montesquieu and Locke. They were the more influential of the group you have.

Locke - don't forget right to revolution
Voltaire - monarchist and anti-religion. Probably government neutrality in religion.
Rousseau - The Social Contract, society is a contract with duties on both ends, the people to obey laws made by the will of the people and the government to be an expression of the will of the community, he was more influential in the French Revolution

However your pursuit of happiness can not preclude me from pursuing happiness and each of our ambitions are not able to avert any one else from gaining happiness both. Which means that there are, of necessity, traditional limits upon pursuit of happiness. God does not ship any person wherever. Your alternatives are what condemn you to an eternity of struggling and suffering, or an eternity of existence in the presence of God. Can't blame God since persons are enormously brief-sighted when making selections in life. So, I do think in the statement of Independence for the reason that it does no longer result in entire freedom to do whatever one pleases. Existence and liberty are rights given to every individual upon being born into this world.