Same here. (Except once I chose on #4, I knew the answer to #9.)

For Hitchcock, I would have thought reading entrails.

Me too!

Likewise 8/10

Not me. 😁

Also " The Festive Season" S 3 E 31, but they covered that in another story:

https://www.metv.com/stories/alfred-hitchcock-knew-the-true-meaning-of-a-black-christmas

The frame of Hitchcock bricking up the fireplace is from " Santa Claus and the 10th Avenue Kid "
Hitchcock says it in the episode intro:

Sorry, it's because seeing that image reminds me of how the killer in HFC buries his wife in the basement!

Other episodes taking place at Christmas are
Together
Cheap Is Cheap
The Dusty Drawer (Thanksgiving/Christmas)
Gratitude
A Jury of Her Peers
The Second Wife

And of course. . .

Yep, believe it or not, the Hitchcock theme Is a classical piece, probably selected because of public domain! Still, it's pretty catchy...LOL!

Hitchcock remembered hearing the music in the 1927 film " Sunrise: A Song of Two Humans."
The music made enough of an impression on him that he chose it as theme music for his television series. Not sure if Hitchcock chose it based on it's " public domain " status, but it's possible.

He heard music in a silent movie? Technically, most silent movies had a live organist playing mood music, and some late '20's films had prerecorded music on records! And of course, The Jazz Singer with Al Jolson came out that year, so it's credible!

Sunrise: A Song of Two Humans is a 1927 American silent romantic drama directed by German director F. W. Murnau.
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Murnau chose to use the then new Fox Movietone sound-on-film system, making Sunrise one of the first feature films with a synchronized musical score and sound effects soundtrack.
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The film incorporated Charles Gounod's 1872 composition Funeral March of a Marionette, which was later used as the theme for the television series Alfred Hitchcock Presents.
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Don't write the historical background, nor challenging it's authenticity or technical points. As to whether it was public domain or whether it was chosen for that reason, it's possible.