Just to be clear, the connections with occult practices is very diverse. Going back to the early days of Salem, the famous witch trials was really an issue of mass hysteria and people simply being idiots and prejudiced. So I consider that all separate.
We have the Skull & Bones organization in Yale and I know about as much of that as you do. All I can tell you is that it exists and it's a bit weird. I saw an event of theirs once. Or at least part of it. I was in New Haven and saw about 3 dozen of the most beautiful blond-haired college girls all wear white robes and victorian masks. They were just walking and not speaking. I asked one of them what the hell was going on and she replied "Secret fraternity stuff" and walked away.
As far as the Freemasons go, there's probably a lot in CT. I'm not a mason, by I have a good friend who is, and my father, before he died, was in the application process. What I know of the masons is limited, but that they are a fraternal organization. That it is a requirement that they believe in a monotheistic higher power, (i.e. God), but that isn't specific. Meaning you can be a Jew, a Catholic, a Christian, and possibly agnostic as well. But not atheist. The people that I have been known to be masons were pretty well established Catholics or Christians with a strong aversion towards the occult, satanism, or witchcraft.
Personally, I'm not aware of any valid arguments for the occult with Sandy Hook. It's not a theory that I currently support.
All that being said, I can tell you that I am a member of a smaller secret fraternity, I won't mention the name, but it doesn't reside in CT. In this fraternity we do use some symbolism, such as that of the skull and bones, and we have a handshake. But the purpose of this secret fraternity is to instill values, positive, not weird or culty values but things like leadership, respect, etc... I believe the root this particular organization is a preparation for a person to advance to a higher level for induction into a group like the Skull and Bones. I know for a fact that my fraternity has ties to Yale. But despite occult symbols, it is in no way actually related to the occult and there is no worship of any kind involved.