To be honest, looking at the translation, I don't think they were kidding. Now, it could be Lightning as a statue or a pet or something, or it could be putting Lightning in as a NPC for some sort of sidequest. There's nothing planned in per say, but it looks like the seed's been planted.

Now, with that said, I really do hope that Lightning is in the game somewhere, but not as part of a main story quest, but perhaps as a side quest or even just a battle character. I think it'll be interesting to see how this turns out.