Recently I had a client who wanted the site hidden until ready to launch on Facebook, I used a plugin to hide the site, but then we had a bit of a hitch, as google didn’t of course know we wanted to launch the site, and therefore was still saying it was hidden, we tried all the tricks in the book, sitemaps and so on and yet it was still showing password protected, much stress ensued, then I tried one last thing, which was to clear the Facebook cache and HALLELUJAH it worked, so the moral of this story is…. unhide a site a few days before you want to announce it, and if Facebook is still not playing ball then have a go at clearing their cache. https://developers.facebook.com/tools/debug/og/object/