<<Then you wouldn't have a problem with listing the colonies and states that did establish religion>>
The only one I know for sure that did was Virginia, as a colony. Once they were states, I didn't think they COULD establish a religion. That's a good question, but I'm not sure where you're going with it.
<< . . . or perhaps an examination of the Danbury Letters in context>>
I confess, the first time I ever heard of the Danbury Letters was in your post here, and I thank you for that, so I Googled them and found the final one - - which seemed to be a pretty firm but diplomatic rejection of the state getting into the religion business. I don't think I have the time to examine the entire correspondence in context, at least not before I retire, but why don't you tell me what you think they signify?
<< . . . or mentioning to students that the US govt under Jefferson funded missionaries or that one of the first official acts of congress was establishing the position of chaplain for both houses.>>
The old "Two steps forward, one step back," eh? Sure it's surprising, I'm not sure if the chaplains were always Protestant ministers, because I know Washington made sure that a Catholic priest and a rabbi were in attendance as well as the ubiquitous Prods at his inauguration. Don't know if he wanted to cover all bases, or was just an early believer in diversity.
Is all that brainwashing or just throwing in some little-known historical fact? I'm very suspicious of the "historical fact" approach, simply because almost all of it seems to favour the conservatives in one way or another. So without necessarily questioning whether the new additions are factual or not, and assuming they are, it's still likely that these are indoctinational facts which favour conservative views. It's a fact, for example, that the UNCAT, which the U.S. signed and ratified, prohibits torture, defines torture, and imposes an obligation on all signing states to prosecute those who have tortured, but if this fact isn't already in the Texas history textbooks, I'd be extremely surprised if the GOP hacks who are so zealously adding more facts to their textbooks would want these particular facts added. As we all know, there are facts and there are facts. So maybe the way to ensure that fact and not propaganda is put in the textbooks is to have the content selected by independent scholars nominated in equal numbers by the two political parties. What you see now is a GOP-dominated commission forcing its "facts" onto the textbooks that children of both political parties are going to be using.