Actually, Miis aren't on the list. I wouldn't be surprised if they aren't in the final game - they are part of the Wii/Wii U era Nintendo seems to be trying to leave behind.GmanSir said:https://twitter.com/Blazingflare apparently datamined the demo may have discovered the rest of the cast:
The 5 Unlockable characters in the demo:
Waluigi, Rosalina, Chain Chomp, Toad, Spike
Other unnanounced characters:
Diddy, Koopa Troopa, Para Troopa, Shy Guy, Kamek, Birdo, Boom Boom, Dry Bones, Blooper, Dry Bowser, Miis. Unknown if all will be part of the base game when it launches.
Bosses:
Petey Piranha, Gooper Blooper, boss_icegolem, boss_esterkoopa, boss_mirage, boss_statuekoopa, and inishienoudedameshi. Audio for Eyerok and King Boo have been found, so they may be tied to boss_esterkoopa, boss_mirage respectively.
My guess about Iggy's ship being in but Larry Koopa not despite him being a tennis player is that they want to keep the RPGs as a seaparate entity now - Larry can be a tennis player in SSS but that tells nothing about the Larry in the Super Mario games and the games inspired by them.
A similar reason why Ludwig isn't there as well despite him knowing Table Tennis - Mario & Sonic is its own thing.
Wendy might have remained as a way to keep the male/female ratio but I guess she isn't high in the priority list of Nintendo and possibly the most vocal Mario fans...