The peasants, therefore, could not accurately study geography, astronomy, even physics, perhaps, as well as other studies which were reserved for Lords. It's a way of keeping the serfs in their place. If they can't study science, that's just one less possibility for them, and that's what the superiors would want, because they need them for unskilled labor.
Yea, ok, but if the conspiracy didn't really start until NASA discovered the truth, then there wasn't conspiracy, only misinterpretation. The peasants may not have been able to study geography and astronomy well (that knowledge would unlikely get them rebellious, but I won't argue that point), but the nobility would be studying the same RE model, and so no one would be studying geography and astronomy correctly. Had the serfs studied these topics, they would learn what the noble scientists know, and do just as well in the field (theoretically). It would be much more beneficial if the nobility did
what they actually did: impoverish and tax the peasants so that they cannot get an education, thus nullifying the need to "make up" an alternate earth theory.
I noticed that you said "among other things that didn't come to the top of my head," so I guess I will wait if you have a different answer.
EDIT: OK, I just realized this: Yes, knowledge of physics could spark revolutionary ideas (Locke's tabula rasa, etc.) but physics on a middle world scale is the same in FE as RE. If nobles wanted to inhibit the learning of physics they would have preached that God or magic made the world work, or something of that nature.