It doesn't replace files. It uses memory injection on original game files, which are applied in real time as the game runs and accesses the files. When you exit the game, the memory injections are cleared and your original game files are still intact. If you were to use Proud Clod, you would need to use the unpack tool in 7H to unpack the IRO file that contains the scene.bin, modify the scene.bin, then repack the IRO file to use with 7H.
You don't have to do any research or testing. Files used for the memory injection are not modified. They are taken straight from the download links found in the mod OPs. You would be wasting your spare time trying to check on issues that are almost always a simple user error with the 7H setup (e.g. load order or mod incompatibilities).