I'll take a stab.
First, I agree with the spirit of what you are saying but it is a little too Disney. The founding fathers had different perspectives and many disagreements. The claim that we are not a Christian nation would've not held true in the 1700's. What the founding fathers all agreed on is that we should not be a theocracy. Many during that era were very suspicious of Methodist and Quakers for being loyalist to the British empire. You can say the battle that was happening at that time was within the different sects of Christianity itself.
Second, we were very much a "white" country for whites. So much so that even later in the 1800's we set up schools to turn Native Americans into "whites" and disown their "savage" customs and heritage.