We can only speculate on what hardware Ken Thompson likes most, or what annoyed him about macOS, he didn't tell. The article only deals with your question #3,

We can only speculate on what hardware Ken Thompson likes most, or what annoyed him about macOS, he didn't tell. The article only deals with your question #3, and the answer is yes, everything's working. As of the fourth question, the key message seems to be: don't buy a Framewok or System76 Linux laptop... the best Linux laptop is a Mac.