Great list! I just discovered this thread thanks to this year's Facebook post, but most of these have been on my personal Halloween playlist for years
"Devil's Advocate" (https://ocremix.org/remix/OCR02113) is still one of my all-time favorite Halloween tracks, right up there with "Koopa vs. Kefka" (https://ocremix.org/remix/OCR01542) and "A Clockwork Vampire" (https://ocremix.org/remix/OCR01401).
I'm also loving the Mazedude and "Vampire Variation" album representation on this list.
1 more from VVVIII I think is a great Halloween track is "Selva Oscura" (https://ocremix.org/remix/OCR03540), though maybe that one doesn't fit the same spooky vibe as the other tracks on this list, so "Deforestation" (https://ocremix.org/remix/OCR02375) might be a better fit.
I also have some FFVI Phantom Forest remixes on my personal playlist.
I consider "The Endless Stair" (https://ocremix.org/remix/OCR02721) a Halloween essential as well.
"The Moon of Bowser" (https://ocremix.org/remix/OCR03372) has become another essential on my playlist.
Of course, plenty of other great Halloween tracks can be found with this site's Halloween tag