How do we know all these new Mario characters are playable in Mario Tennis again?

[CM30]

Like Luma? Call me a bit insane here, but do we have any footage showing it in a mode other than the Galaxy Tennis one?

 

[tdimodel6]

Luma and baby peach @22:09
http://www.youtube.com/watch?v=xbobssGDL4U

 

[tdimodel6]

so im thinking the official 16 are:
1. Mario
2. Luigi
3. Peach
4. Daisy
5. Wario
6. Waluigi
7. Yoshi
8. Koopa
9. Bowser
10. Bowser jr.
11. Donkey Kong
12. Diddy Kong
13. Boo
14. Luma
15. Baby Mario (unsure)
16. Baby Peach
known unlockables:
Dry Bowser
guessing these are unlockables:
Rosalina
Baby Luigi
Baby Daisy
Shy guy
Paratroopa
Wiggler

and then you also have Mii, not counting as Mario character

 

[Darking]

Yeah, that's a pretty reasonable list. But I hope they include Petey too. He's lost in oblivion.