My Illogical Theory
Well, yes. The Fairy-type will be introduced at some point.
Since Arceus, to my knowledge, has only ever been introduced once in the anime (Arceus: The Jewel of Life) I don't think it will be introduced again. Esepcially since Celebi hasn't been referenced again since the Pokemon4Ever movie. (or whatever it was called xD)
In the games, the professor's assistants that stalk you throughout the game reference the new Fairy-type quite happily. So they will probably run you through the new Fairy-type. How, I don't know. They will probably say something like:
>It turns out some Pokemon have Fairy-type DNA like Azumarill and Mawile! It's a great discovery to us Pokemon scientists.
...I don't know. They will probably mention it, though.
That's all I can think of now, and I'm in a rush, so I'll edit in anything else if I think of something.
My point is, they will mention the inaugural of the Fairy-type.
Hope I helped. :)