http://gonintendo.com/?mode=viewstory&id=175940
New trailer from Nintendo Direct.
Customizable Mii costume ( I am going to dress my Mii as Fire Mario)
and Baby Peach and Luma were shown so confirmed playable. I will update the character list ( going to automatically add babies Mario and Luigi because of Peach.
and 16 characters total so
we have the 13
plus the Baby Peach + Luma that is 15 confirmed, whoops so either I am wrong about both baby or Mii is not in the count
Well, the supposed 16 character total comes from the Japanese site's character section, which shows 12 characters (no Mii) and 4 question marks.
With Mii having an entire section of the site, I doubt he'll be one of the question marks.
Also, note that the 16 character total is not confirmed. These sites don't always show all characters.
With what we know now, there'd be space for 2 more, of which one should be Baby Mario, now that we know Baby Peach is playable.
And we only know one Defense character so far, so instead of adding Baby Luigi, who would probably be another Speed character, like Baby Mario, they'll probably add another Defense character, like Wiggler.
We've also seen costumes of Koopa and Fire Mario, and so far all other costumes have been of playable characters.
However, there's also normal tennis wear you can buy based on Bullet Bills, Chain Chomps and even ? Blocks, so it might not mean anything.
But even then, I think it would be really mean of Nintendo/Camelot to make it possible to play as a huge-headed Koopa with a Mii face in its mouth, talking and moving like a Mii, but not Koopa itself.
Characters like Toad, Toadette, Shy Guy, Birdo are also still missing.
Then again, they could just keep it at 16, like with Mario Kart 7, but I really hope not.