I think it's either going to be that or Psyduck. The writers might find Togekiss a little too predictable... but wait a minute, these are the writers for Pokemon. Togekiss makes sense since it's a high profile Pokemon, and Misty's is the Togepi/Togetic for the whole show. It would be the best way to feature its second evolution in the show. The only problem is that it might be a little hard to find a credible way to bring Togetic back. They could probably do it, but... I think Psyduck is also a good option. Psyduck was popular while it was on the show, and it would be good for ratings to feature it again. If we're lucky, maybe we'll get two cameos... but I doubt it, somehow. Then again, May stayed on for several episodes. The writers might want to give Misty equal screentime... they'd have to divide it up, but still. But then May had never had a cameo before, whereas Misty had had one plus the Hosos... There's really no telling how it'll go.