When I downloaded the game, the halloween stuff and various other maxis created things came along with it. Back when I was on windows, it was also inaccessable. When I moved to Linux and had to use magipack in order to download the game due to a multitude of issues, I thought my problems were solved. There was a folder labelled "Bonus Content" that had all the store stuff that I didn't want in it. Well, today, I finally had the energy and time and decided to do a purge. Deleted all the Cas stuff that had been plaguing me from that folder.

Nothing went away. I tried searching the programs files for one of the stupid things and nothing showed up. I specifically searched for "anime" since one of the things I'm trying to get rid of is the anime hair, and nothing showed up. I looked through my whole file system, essentially. It's like they don't exist. Is there like, some prebuilt storage location where they are hiding with different names?

All of the store stuff is in the form of files that go in Downloads. If you have it installed, it'll be there. There were some files labeled "anime" in the Asian hairs, maybe you're thinking of those? I think I have all of the store stuff, this is the complete list of Asian hairs I have in there.

It (along with the others) was in the download folder. I don't know if my game just hadn't deleted it yet yesterday (as in, there was a delay for some reason) or if it was in one of the various things in the preorder content (which I went through this morning), but when I came back today everything that plagued me was gone.
So all is solved, I guess.

CAS stuff can get cached, which is why you should delete the cache files when changing up CC. I don't know if stuff that you've deleted from the folder can still show up and work due to that, though.

For the cache files, they only save a "shadow copy" of sorts for quicker loading, but this copy still needs the files to work.

The cache files can show old versions of meshes (possibly recolors?) if an item has been updated and the files are available (old mesh only shows if a sim has been saved with it before the update, is fixed with a mirror), and it can show a placeholder mesh if an item a sim was wearing has been removed (white mesh w/black writing, usually for accessories/hair - goes away in the mirror), but I don't think it's able to cache a full item.

If the mesh and recolor files aren't available, the entire item disappears from the catalog even if you haven't deleted the caches (the only exception being the occasional item sims are wearing, which turns into the white mesh w/black writing, which disappears in a mirror).

You most likely still have a copy of the item in your files as long as you have both the texture and mesh showing up in CAS.

The cache files can cause other issues with CC/mods, so remove them if you've done changes in your downloads, just in case.