I've seen this mentioned a few other places, so I figured I'd share:
If you watch this video at around 0:56, pay attention to Pikachu's square and you'll see another confirmed character.
Really happy to see that Shulk is in, as he'd been on my wanted list since I finished Xenoblade about a year and a half ago. I recently began to think Melia would make for a more interesting fighter, actually, but I'm just glad Xenoblade is getting any representation at all (and Sakurai made it...