Yep, the Waveshell can indeed be confusing, but needs to be correctly in place for any Waves plug-ins to appear in your VST list.
Reaper is available in both 64-bit (Windows x64) and 32-bit versions depending on which version of Windows you're running:
https://www.reaper.fm/download.php
However, if you've installed 64-bit Reaper, it has a wonderful built-in bridge that can automatically run any older 32-bit (and even DirectX) plug-ins in your collection as well. It works beautifully for me!
Martin