Sorry if this is considered a bump, but I think I found one of the missing songs!
Decompiling the game with FFDec, I found that "Fourty Below" is internally referred to as "SnowMan", so I searched for "SnowMan" here, and I found
this, which seems to be a match.
However, this file is slightly different from the version in the game: the two most major differences are that the tempo of the in-game version is slower and that one of the original file's melodies seems to be bugged on the first listen (it works properly and matches the in-game version after it loops). This means that Jindo most likely slowed down the song and fixed the broken first loop for the game.
Additionally, what I've been calling the original file gives "respect to the original song" without specifying what "the original song" is. Maybe it's another mod file, maybe it's Celtic Woman's "Walking in the Air" (which "Fourty Below"/"Snowman" sounds somewhat similar to), and maybe it's something completely different. I don't know!
[EDIT 2021-12-12: OK, it looks like it most likely is based on Walking in the Air, because apparently it wasn't originally a Celtic Woman song (I only thought it was because of a Kongregate comment that mentioned it), but a song by Howard Blake for the film "The Snowman". Given the thematic similarity, I think this is likely the "original song" the file was talking about. Also, this is a tangent, but the key of all three versions of the song is somewhere between D and D# minor. Interesting!]
The main menu theme is still missing. Additionally, the OP missed Funky Switch (the song used in the two bonus worlds), and I was unable to find its source. (And, no, the internal filenames for these songs are not helpful for either of these, since they're just "MenuTheme" and "FunkySwitch" respectively.)
Here is a YouTube video of Funky Switch, uploaded by me, because I don't think there were any videos before this of just Funky Switch.
Oh, and just for posterity, here's a list of found sources for all of the songs in the game:
Main Menu ThemeTrick QuestionFourty BelowIce EyesTricky RealityFunky SwitchUpdate 1 (2021-12-21): I attempted to reach out to Jindo through a YouTube comment to see if he knows what and where the sources are, but sadly, it looks like he does not remember them, and cannot even try to do a proper search for them until the new year.
Update 2 (2021-12-26): Both the Main Menu Theme and Funky Switch have been found. Wow. However, I cannot take credit for finding them. Essentially, I posted information about the songs in the Discord server for another Flash game called Snailiad, and Plane (who happens to also be Auriplane, the creator of Snailiad) went ahead and took some time out of her day to write code to find the songs. She wrote a program that output all of the notes in all of the tracks of a given tracker file in order, and then ran that on all of the tracker files in the torrents in an attempt to find a sequence of notes from the original song. And this worked (although the main menu theme was pitch-shifted, so she had to use relative pitch for that one.) Now we know that "Main Menu Theme" was originally Eclipsed by Bzl, and "Funky Switch" was originally 4 NoRFaiR by JosSs. Anyway, the list of found songs has been updated to now include the files for these, so everyone can enjoy them now!
