Great list, with well thought out criteria.

Have to admit I'm not sure about listing something as recent as Knives Out in "classics", but it is a great read, not to mention satire, of the whodunit genre.

Love Gosford Park, LA Confidential & Witness For The Prosecution in particular.

One enduring mystery to me is the changes to Name of the Rose. Granted they had to simplify Eco's philosophic meditations, but the name of the rose being the girl!?! Come on!

[spoilers to the book if you haven't read it]

Of course the girl is "burnt flesh" as Brother William points out. He uses his past as in Inquisitor to intimidate the monks, it's no great secret or shame to him. I do get why those changes were made. But why was Connery's Brother William so prissy over learning that his protoge had "transgressed" with the girl? In the book William tells him that while did sin, it's not a bad thing for a priest to have a wide range of experiences to use in counseling his flock. In fact, William almost seems jealous of the experience.

And I think, in closing, Eco got this point wrong. Prior to the Reformation, priests were expected not to marry, but I don't think strict celibacy was enforced or expected (e.g. two centuries later Pope Alexander VI's children, Casare & Lucrezia Borgia were known to be his progeny, even though they called him "uncle" in most public settings—didn't stop him from being elected Pope).