Renaming pp2/cr2/etc should work…if nothing else calls them. Renaming the icon files that go with them…absolutely necessary to match the name of the png to the name of the associated file (so My_item.cr2 must have a png icon named My_item, not My Item).
Renaming textures, obj, folders they are in and stuff like that…yeah, breaks things. PP2s/cr2s with included geometry…moving probably will be fine, but if they call something else, all bets are off.
Also, depending on how the path information is written, within the files, matters. If everything is completely relative, then things can be moved..but any ‘hard’ paths and no, no moving allowed. I’ve found that it’s best to set up a separate partition/drive for content and install it all there and do any organising within DS, by using Categories/whatever and not try to actually rearrange the files themselves. Sort of ‘soft organise’ them…
And…yeah, Smart Content itself isn’t all that smart. If you start moving/renaming stuff, especially outside of DS, it will break. If you move it within DS, maybe you can get away with it…rename, probably not without actually loading/resaving.