Marth Debuted in Smash Bros.: Footage and music from Final Fantasy Type-0 is retained in the Western releases, despite the West not getting Type-0 till the HD remake in March 2015. And of course, there's "Somnus" from what was then Versus XIII and is now Final Fantasy XV appearing in the original game, although it's conspicuously absent in the iOS port and Curtain Call.
No Export for You: Highly feared at first, given the game's nature as one hell of a Widget Title. But then it was announced for the other regions. Averting such a trope is already a great feat for Square Enix, let alone the aforementioned nature of the game.
Played straight with the 3DS' DLCs in areas without Nintendo eShop Access (which is a rather huge chunk of Asia, parts of Africa and quite a few East European countries).
What Could Have Been: Theatrhythm was originally planned for the DS, but was moved to the 3DS due to greater storage capacity.