I already did a massive blog post about what my ideal roster for a Mario spin-off was, but after Super Mario Odyssey, some updates should be noted. I'm not going to rewrite the whole thing again, instead, I'm just going to do a basic outline which hopefully will be self-explanatory. With that in mind...
Confirmed
Mario
Luigi
Wario
Waluigi
Donkey Kong
Sure Thing
Peach
Daisy
Yoshi
Bowser
Most likely
Toad
Bowser Jr.
Rosalina
Since they already have models for them from Ultra Smash
Toadette
Boo
Sprixie
Characters who SHOULD be obvious inclusions but might get passed over for who-knows-why
Diddy Kong
Birdo
Cappy
Pauline
Chargin' Chuck
Characters who will probably be included even though I'd hate it if they were
Baby Mario (well, I guess I wouldn't mind as much if it were only him)
Baby Luigi
Baby Peach
Baby Daisy
Baby Rosalina
Dry Bowser
Metal Mario
Pink Gold Peach
Other characters I wouldn't mind seeing
Shy Guy
Koopa Troopa
Koopa Paratroopa
Wiggler
Petey Piranha (doubt it since he's a boss, but still possible)
King Boo
One of the Broodals (most likely Topper and maybe Hariet)
Dixie Kong
Larry Koopa (if any Koopaling makes it in, I hope it's him)
Kamek
Nabbit
Funky Kong
King K. Rool
Dry Bones
Hammer Bro
Monty Mole
Pianta
Noki
Whittle
Tostarenan
New Donker
Shiverian
Boom Boom
Characters who definitely won't be playable in this game but I'd want to see anyway
Donkey Kong Jr.
Foreman Spike
King/Big Bob-omb
Blue Bowser (Bowser's brother from Super Mario Bros.: The Lost Levels; I like to call him Bluser)
All Seven Koopalings (one or two of them, maybe, but all seven, highly unlikely)
Toadsworth
Professor E. Gadd
Cranky Kong
Mouser
Wart
Tatanga
Captain Syrup
Ashley (from WarioWare)
Stanley the Bugman
Il Piantissimo
The Chimp
The Kings from Super Mario Bros. 3
Mad Scienstein/Dr. Arewo-Shitain
...And that about covers it I think. Here's hope Nintendo surprises us some more with this game (and GOOD surprises at that).
