FF9 is good just for Vivi's story, and its cheap on steam/psn right now. FF6 is a great game, I haven't played it in years and years, not sure how well it has aged, or where the best place to play it would be, likely steam. FF4 is..skippable. But you can easily play it on emulation, that's what I would do. I wouldn't pay for it.
I wish I could find a good version of the guide. Only decent one I've ever found was a paperback that was insanely expensive. Alternative is to find somebody to rebuild the site lol...