People also expected Toad, Waluigi, Paper Mario, K. Rool, Dixie, Cranky, Impa, Ghirahim, Tingle, Bandanna Dee, Krystal, Ridley, Dark Samus, Metroid Hunter, Zoroark, Kalos Trainer, Medusa, Hades, Louie, Tom Nook, Isabelle, Takumaru, Dillon, Wonder Red, Isaac, Ray, Bayonetta, Saki, Prince Sable, Simon Belmont, someone from Square Enix, due to how popular they were.
Not really. That's a pretty broad definition, and even then, half of these weren't "expected" by anybody. Some thought they were "likely," but "expected"?
Toad, Waluigi, Paper Mario, K. Rool, Dixie Kong, Ghirahim, Tingle, Bandana Dee, Krystal, Ridley, Zoroark, Tom Nook, Takamaru, and Isaac are the only ones on there that a significant number of people truly "expected" at one point or another, and most only thought these were somewhat "likely."
Cranky had a decent fanbase and many wanted him over K. Rool/Dixie, but I can't think of many that outright "expected" him over Dixie and K. Rool. Impa was never really expected by anyone (ok, I guess I did expect her prior to Sheik's reveal, then most wrote her off), nor was Dark Samus or... Metroid Hunter? Kalos Trainer was a semi-common suggestion, but again, can't really say it was "Expected." Many wanted Hades, and several thought Medua was the next-best choice, but I can't think of anyone who "expected" them.
Louie, maybe. I expected an AC character and thought Tom Nook was a good choice. Isabelle? Again, maybe a semi-common suggestion. but its not one really brought up that much. Ray, Saki, Bayonetta, and Simon Belmont were fairly common suggestions as well, plus a plausible SE rep.
Prince Sable and "Metroid Hunter" were niche suggestions in the best-case scenario.
There's a huge difference between supporting a character and thinking a character was likely or a viable option, as opposed to blatantly "expecting" a character.
EDIT:
As for the whole Chorus Kids debate, I still say Karate Joe is much more prominent. I guess the style of character of the Chorus Kids have been in every game, but the Chorus Kids were really only in DS (and now 3DS). Its a stretch to say that character in Rhythm Heaven Fever is nothing more than another character of the same "race."
And its notable that Marshall appears in Rhythm Heaven GBA, too. The Night Walk game debuted there. He wasn't really given a name in that game. Then in Fever, Marshal was in that game and then did Night Walk in the credits. Its debatable if its Marshal in both games, but they look very similar and do the exact same minigame.