There are different types of conspiracy theories. Those you think are true, those you know are true, and those you hope to God aren't true. This is one of those.

The Great Pyramid of Giza

Link doesn't work on my end.

I've had a similar theory for a long time. In 1 Kings 6 the architecture of the temple is described. It had the main court that occupied the temple mount, and then there was the inner sanctum where the Ark of the Covenant was. This room was only accessible to the high priests. I suspect the structure of Freemasonry is the same way. The Temple of Freemasonry has its main courtyard where the majority of masons dwell, while the inner sanctum is for the fraternity within the fraternity.

I see. One thing I have heard about Mormonism, but never really looked into, was that its origins and temple rites are Masonic in nature. What do you think about that?

Not sure if you're an atheist or a really low-church protestant...

The entire idea of the "dark ages" itself is a giant conspiracy. All made up by "enlightenment" figures high on their own superiority complex.