Cool!! Please play!
My reactions are that your approach is close to mine, but for the last two.
I look at this and (2) strikes me as a big problem, despite the lack of "state action" in the threats themselves. This is the one issue on the list I think someone in government ought to do something about. It's a free speech consequence of failures elsewhere in the system, and if we worry about private action chilling free speech, we ought to be
much more concerned with a physical threat than a person being mean to someone with whose views they disagree.
I generally agree with you on Trump calling the press the enemy of the people. The crux of whether that one is a problem is whether his words carry policy with them, and so represent state "action", and I think they are too vague to do so. The real problem here is not that Trump says these things, but that they resonate with such a large portion of the population.
I would move Liberty University up a notch - you've suggested there is a sort of implied consent when you sign up for the program, and that is an excellent point (applicable to many Catholic Schools, too). This is really about academic freedom rather than free speech, and the extent to which prior censorship is acceptable in an academic world. This is, however, an actual example of "political correctness" being policed by a private body - Liberty can do something to the student newspapers' volunteer staff other than just say mean things about them and publish their work.
Details on what is happening at Liberty are here.
In reality, I only think (2) is a problem that needs some action from the state to address, two of the remaining three are things to jaw about and the last one, where the response to bad speech is more speech, is just a place to pile on and has absolutely zero relevance to any discussion of free speech other than as an example of how free speech actually works in a Democratic society.
