The United States was founded by God-fearing, Bible-toting, Fundamentalist Christians, right?

Answer 1

John Adams, believed in the essential goodness of the creation, but did not believe in the divinity of Christ or that God intervened in the affairs of individuals. He advocated the separation of church and state, but he also believed that regular church service was beneficial to man's moral sense. "Adams strove for a religion based on a common sense sort of reasonableness"
Adams was clearly no atheist “I have attended public worship in all countries and with all sects and believe them all much better than no religion.

Benjamin Franklin became disillusioned with organized religion after discovering Deism, but he still recognized the value of religion in the lives of mankind. "If men are so wicked with religion, what would they be if without it."
Franklin displayed his conviction of a deity that was intimately involved in human affairs by requesting that each day's session begin with prayers. Franklin recalled the days of the Revolutionary War, when the American leaders assembled in prayer daily, seeking "divine guidance" from the "Father of lights." He then rhetorically asked, "And have we now forgotten that powerful friend? Or do we imagine that we no longer need his assistance?"

Thomas Jefferson - Jefferson was a deist because he believed in one God, in divine providence, in the divine moral law, and in rewards and punishments after death; but did not believe in supernatural revelation. He was a Christian deist because he saw Christianity as the highest expression of natural religion and Jesus as an incomparably great moral teacher. He was not an orthodox Christian because he rejected, among other things, the doctrines that Jesus was the promised Messiah and the incarnate Son of God. Jefferson's religion is fairly typical of the American form of deism in his day.

George Washington = Washington was the most religious of those one might consider to be the founding fathers. Washington endorsed religion remarking on its importance in building moral character in American citizenry. At least by some accounts, he valued the scripture in a way Adams, Franklin & Jefferson did not.

"Fundamentalism" began in the 1920s as a reaction to Darwin & others. So none of the founding fathers would have used that label, but I bet quite a few were regular church people who you might think of as "fundamentalists" today.

I'm reading up on Samuel Adams & John Hancock right now.

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I have yet to find an athiest among the founding fathers, but Washington is the closest I've found to what one might think of today as a 'fundamentalist."