1. Is private ownership of property primary?
It's up there in the top three for me. Life, liberty, property, not necessarily in that order. Pursuit of happiness sounds pretty but it should have been property.
2. Can a human being be property?
Yes. I assume we will depart ways there. But I also say this on the basis of the Constitution, which allowed for indentured servitude and slavery, both of which forfeit to some degree a person's right in their own selves and labor. I think that it is generally a better principle not to allow such a thing, and that slavery is abolished in the U.S. was certainly the most positive outcome of the Civil War, but it's hard to argue that a human can't be property when they obviously can be, and have been, as long as humans have been humans. You might argue that they SHOULDN'T be, but that isn't the same thing as arguing that they CAN'T be, either pragmatically or Constitutionally (under the unimposed pre-1861 Constitution, of course).
3. Can the SCOTUS overrule State murder laws?
To my reading, no. The eighth amendment states:
"Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted."
The Founders didn't find the death penalty cruel or unusual. There is no Constitutional way it could ever happen that the SCOTUS do such a thing.
4. Is the 2nd Amendment valid?
Where? In states and all U.S. territory? The plain reading of the law says so. "The right of the PEOPLE to keep and bear arms shall not be infringed."
5. Can the federal government insist on religious silence?
Where? I think I need more detail, there, but generally, no. Further, "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;" certainly doesn't apply to the States. States can have their own religion, if they wish, subject to their own limitations, of course. That's part of the reason States were not included here--some did have strong traditions like that as of the signing of the Constitution.
6. Can 49 states ratify an Amendment that compels the sole dissenting state to conform?
Under the Constitution, maybe. It would probably depend on the subject and circumstances. After all, Article I does give the feds SOME jurisdiction, and in the same article, prevents certain other laws that might affect states under particular circumstances (bills of attainder, ex post facto laws). I would generally say that 49 states can't single out another state to comply with a law they don't comply with, but that I don't know the situation you're talking about limits my answer here. No matter the Amendment put forth, in my opinion, the lone State will always have the option to secede, as well.