2125f0a0b9241894 The files in DCCache are bundled Store and custom content, so any items you've installed through the launcher are represented here. Lots and households have a separate entry in Library, sim templates have an entry in SavedSims, and worlds have a file in InstalledWorlds, but that's it. Any recolors you've saved in-game are stored in UserPresets.package, but that's not related to downloaded content. Please see this for more information about your user files:
https://sims3.crinrict.com/en/2011/01/faq-user-files.html
For the items you're trying to install, I would test them one at a time in an otherwise clean Sims 3 folder. If you can't install them even then, they might simply be broken, or at least broken in the 64-bit Mac version. That shouldn't happen in that all content should be compatible, but it is possible.
