Jefferson didn't come up with the "concepts" for the Declaration on his own. If you compare the opening of the Virginia Declaration of Rights" (adopted by Virginia in June 1776)with the Declaration of Independence, you'll find numerous similarities.

Virginia Declaration of Rights

I That all men are by nature equally free and independent, and have certain inherent rights, of which, when they enter into a state of society, they cannot, by any compact, deprive or divest their posterity; namely, the enjoyment of life and liberty, with the means of acquiring and possessing property, and pursuing and obtaining happiness and safety.

Dec of Ind
Preamble
We hold these Truths to be self-evident, that all Men are created equal, that they are endowed, by their Creator, with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness.


Vir Dec

II That all power is vested in, and consequently derived from, the people; that magistrates are their trustees and servants, and at all times amenable to them.

Dec of Ind

That to secure these Rights, Governments are instituted among Men, deriving their just Powers from the Consent of the Governed, that whenever any Form of Government becomes destructive of these Ends, it is the Right of the People to alter or abolish it ..."

In my opinion the "forgotten founder" is George Mason. Jefferson practically plagiarized the preamble of the Dec of Ind.

Mason is also essentially the author of the Bill of Rights.

If you go to DC and check out the Jefferson Memorial, follow the path to the new memorial to Mason. It's a simple and fitting memorial to a man who had a far greater influence on his day than he receives credit for.

As far as Paine goes

"THESE are the times that try men's souls. The summer soldier and the sunshine patriot will, in this crisis, shrink from the service of their country; but he that stands by it now, deserves the love and thanks of man and woman. Tyranny, like hell, is not easily conquered; yet we have this consolation with us, that the harder the conflict, the more glorious the triumph. What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value. Heaven knows how to put a proper price upon its goods; and it would be strange indeed if so celestial an article as FREEDOM should not be highly rated ..."

Perhaps the single greatest piece of writing by an "American." Shakespeare would be jealous.