The first one is a short 1989 letter to Nature. Though very technical it just seems to be an early discussion of the Higgs field metastability. As far as I can tell there is no mention of protons or the Cassimir effect. I looked at the talk page on Wikipedia and there is no discussion of this either. You get that in Wikipedia, some editor adds something, and nobody else checks it and it may often be wrong.
http://ctp.lns.mit.edu/Wilczek_Nature/(72)vacuum_metastable.pdf
The second one is the idea that neutrinos were originally massless and at some point in the recent past they transitioned to having a mass. That clearly was a transition with very minor effects if it did happen - since nothing happened to our Earth / solar system / galaxy etc. Even ancient supernovas which depend on neutrinos to explode seem to behave just like present day ones.
So it is a very minor thing if it did happen. However this is just a hypothesis, and they say that their theory does not provide a clear explanation of certain cosmological discrepancies so that is a point against their theory as a hypothesis.
The motivation for it is to explain a "mild tension" between the red shift measurements and cosmological background measurements for the varying density in the early universe.
It's one of those theoretical studies that is highly unlikely to lead to anything but is still of theoretical interest enough to be published. By publishing it they help others who may be interested to know if a time varying neutrino mass is worth onsidering, and maybe deelop their ideas in other directions. As it is, it's not a very likely theory.
The last one, metastable dark energy is a different theory from the Higgs field and is a modern idea that has several papers on the topic by many authors, the most recent I found was in 2020. It seems to be about an exponential decay like radioactive decay where dark energy gradually over time decays to dark matter. I.e. the dark energy is metastable but it only decays bit by bit rather than all at once and has been decaying like this for billions of years.
https://arxiv.org/pdf/1904.03790.pdf
As a general point, our universe has lasted for 138 million centuries. If it could decay in some abrupt way, then this has to be incredibly unlikely for any given century, or with near total certainty, it would have happened already billions of years ago.
So, any vacuum decay theory has to explain that. If a theory predicts with near total certainty that our universe collapsed over 13 billion years ago, say, then there is something wrong with the theory.
It is sometimes run the other way around, to use observation of our current universe, that it has existed for 138 million centuries as a way to argue that a theory can't be correct if it predicts an easy decay of the universe to some other state