You understood enough of ganbustein's posts to figure out an alternative approach, and if your Finder prefs reverted to factory default, what you did accomplished your purpose.
More: Actually, if you accomplished your purpose I think your extensions should be showing, because it's default, but I don't know if you can toggle them off, because my experience has been that toggling that Finder pref only affects newly created items.
Last edited by artie505; 06/10/18 04:25 PM.