I know you probably don't want to give away spoilers, but if Falkner's included, then... YAY. Because it would be kind of nice to see gym leaders interacting with each other.
Btw Falkner does seem to know Janine in HeartGold; you can find Falkner on the 4th floor of the Celadon Department store with Janine, arguing with her on whose dad is better. :x And we don't even know who Falkner's dad is.
But then again I don't want to guess what Janine's oneshot will be like, because I'll probably be wrong. Anyways, I'm really looking forward to Janine's one-shot.