Friend of American Creation Bill Fortenberry listed some philosophers who influenced the American Founding with links to their understanding of what the phrase "pursuit of happiness" meant to them. It was noted that John Locke in his Essay Concerning Human Understanding invoked "pursuit of happiness." Interestingly, the Locke's famous "life liberty and property" derived from his Second Treatise on government.
Here is a link to Locke's specific use. Here are some other philosophers' use of that phrase: 1. Bolingbroke; 2. Joseph Priestley; 3. Shaftesbury; 4. Joseph Addison.
deck of those four or five seems to be tilted in favor of the thesis that it
was certain "key" or elite figures who possessed more heterodox ideas
that were in tension with those of the more orthodox powers that be.