For example, how do you classify your very first (meta-)claim: "None of them are falsifiable claims about the nature of reality." Is it an opinion?

The snarky answer: It's not a falsifiable claim.

Any claim might be falsifiable if it is adequately specified, so that it becomes testable. If a claim, as stated, isn't falsifiable, it might become so through specification. The author hints at this with:

"Justin Bieber sucks". There are a few ways we could interpret this as shorthand for a different claim.

And some of the "different claims" may be falsifiable.

Ultimately, we could also take unfalsifiable claims as being expressions of some attitude. It's only when we try to determine if they are "true" as applied to some reality "out there" that we run into trouble.

The value of the post is in practicing and developing the skill of ready identification of the whole class of claims that are not factual, i.e., not about reality aside from our judgments, opinions, estimations, theories, preferences, conclusions.