SE'd be stupid to try to sue Chrono Symphonc. The vast majority of its Final Fantasy fanbase is American, and without that, it's dead in the water.
In my mind, fan projects of any kind should fall under fair use, unless they're actively trying to make money for themselves at the expense of the original developers. I can almost guarantee you that Squaresoft wouldn't have pulled that shit. Enix is clearly the dominant entity in the corporation.