"We have documented cases of humans leading normal lives with little to no brain beyond a cerebellum" -- I take this to mean that these are humans that have a cerebellum but not much else.

Your npr.org link talks about the opposite -- regular brain, but no cerebellum.

Your irishtimes.com link talks about cerebrum, which is not the same as cerebellum.

Your biology.stackexchange.com link talks about Cerebral Cortex, which is also not the same as cerebellum.

And the cbc.ca link does not contain the string "cere" on the page.

Your first example is someone without a cerebellum which is not like the others.

The other examples are people with compressed neural tissue but that is not the same as never having the tissue.

A being with only a cerebellum could not behave like a human.