With respect to validity and opinions, I think it is also important to back up your reasoning so that people can determine whether your opinions are well-founded. This is especially important if you change your mind about something!

With respect to immutability, I would tie this to integrity. If you keep your word and follow through, so that your commitments are immutable.

There rest I think is spot on, although I only engage with other crypto users here (already an immutable record) so I'm a bit lax about quoting the original comments when I respond.