I think it's safe to assume that the normal characters will be playable in modes outside of Toad Scramble. That said, who do you think will be part of the roster?
If you want to avoid having duplicate characters, you'll need at least 16 different chracters. So far we've seen:
Mario
Luigi
Peach
Yoshi
Wario
Donkey Kong
Daisy
Waluigi (mentioned on Treehouse Live)
Rosalina
Toadette (confirmed through fact sheet)
From there we also have the following characters through amiibo:
Toad
Boo
Diddy Kong
Bowser
Toad will likely be playable in the other modes but not Toad Scramble, so let's assume he doesn't count in the 16. Bowser is a boss, so let's rule him out as well. With that, we have four more characters that haven't been revealed.
The next group of characters were all playable at one point in the Nd Cube games. Kamek is a boss and Bowser Jr. will likely have a different role, so my guess is that Birdo, Koopa Troopa, Shy Guy, and Spike are the last four characters.
Birdo
Koopa Troopa
Shy Guy
Kamek
Bowser Jr.
Spike
If you want to avoid having duplicate characters, you'll need at least 16 different chracters. So far we've seen:
Mario
Luigi
Peach
Yoshi
Wario
Donkey Kong
Daisy
Waluigi (mentioned on Treehouse Live)
Rosalina
Toadette (confirmed through fact sheet)
From there we also have the following characters through amiibo:
Toad
Boo
Diddy Kong
Bowser
Toad will likely be playable in the other modes but not Toad Scramble, so let's assume he doesn't count in the 16. Bowser is a boss, so let's rule him out as well. With that, we have four more characters that haven't been revealed.
The next group of characters were all playable at one point in the Nd Cube games. Kamek is a boss and Bowser Jr. will likely have a different role, so my guess is that Birdo, Koopa Troopa, Shy Guy, and Spike are the last four characters.
Birdo
Koopa Troopa
Shy Guy
Kamek
Bowser Jr.
Spike