You probably know this already, but Yahweh's prominence on the coinage and in the Pledge of Allegiance is a relatively recent phenomenon. It wasn't until 1908 that 'In God We Trust' was mandated on the coinage, and 'under God' wasn't inserted into the Pledge until 1954, as part of a wider anti-communist reaction. The supposed areligiosity of the Founders is often overstated by modern-day atheists with an axe to grind. However, while you'd be hard pressed to find a more pompous and puritanical Christian than the likes of John Adams, even he was strongly supportive of the separation of church and state: "Nothing is more dreaded than the national government meddling with religion."