These have not been confirmed in no way. These where taken from the videos that Nintendo released, I think.

Medium Weight:

Mario
Luigi
Peach
Daisy
Yoshi
Birdo
Waluigi
Magikoopa ( Kamek )
Shy Guy

Light Weight:

Koopa Troopa
Paratroopa
Baby Mario
Baby Luigi
Dry Bones

Bowser Jr.

Toad
Toadette
Diddy Kong
Blooper
Noki

Heavy Weight:

Bowser
Wario
Donkey Kong
King Boo
Petey Piranha
R.O.B
DK Jr.
Hammer bro.
Pianta
Monty Mole

Link