I read that as that was the last time we would be seeing her, not the other way around. As in, it could just be a hint that SE are retiring the Songbirds for the Little Ladies Day event and trying something else next year. We'll see either way.

Also our character has plot armour as we are the 'main' character so we have nothing to be afraid of in that regard (they never kill off the 'main' protagonist in any FF game, at least not until the story is complete. And I doubt they would hint that in a seasonal event quest). Because without our character, there is simply no storyline.