I don't know how "founding fathers" usually gets defined... members of the Continental Congress? Signers of the Declaration of Independence? I also realize that religiosity is a complicated beast, too--behavioral religiosity? Acceptance of values? Personal belief?--but I'm hoping someone somewhere has taken the plunge, operationally defined these things, and tried to inform this question.
I guess my overall question is: was the USA founded by people who were more religious than, less religious than, or about as religious as other Americans at the time?
They were clearly courting liberal positions for their era. They were far more educated the the average American so had ethical outlooks beyond religious books.
The concept of 'Life, Liberty and the pursuit of Happiness' simply flew in the face of the religious establisment. Persuing happiness was proposed by Englishman Locke as an ideal and was opposed by Protestant and Catholic ideologies, ie you persue the happiness of God.
Their 'religious tollerence' is very much liberal, as in Europe Catholics or Protestants were persecuted and discriminated against depending on who ruled their respective countries.
Now many of them were probably religious men, they probably were believers as such. But they would as a group see beyond the religious dogma of their own religion.