I don't like that mindset at all. Those few characters aren't the only options for their respective franchises, and this happend in the past.
People were expecting Waluigi, they got Piranha Plant; what's stopping them to put Cranky Kong instead of Dixie as the next DK rep?* Or Funky Kong as a DK echo/semiclone? Stuff like that happend already, it wouldn't be a surprise... with this "next in line" argument people are gatekeeping a lot of characters, especially in series like Kirby where there are multiple ones who have been recurring or had major roles in more than one game already, and the series introduces new character almost each new main game, so we could potentially even get the new character from the new game to shill it a la Fire Emblem.
For Star Fox we got the main character, the main antagonist (excluding Andross for obvious reasons), one member of the crew (Falco), and... next in line should be Peppy or Slippy, but we know that if they ever add another Star Fox character, there's a big chance it's gonna be Krystal, the side character who got a spot in a couple of games and then was neglected by Nintendo as if she never existed. I mean, she's an assist trophy already, and one of the advanced ones with a small moveset, Peppy and Slippy are cameos at best.
This is just an example to say that character selection is not as simple as "he/she's next in line", else Toad would have been in Smash since Melee, or Tom Nook would have been in place of Isabelle.
*(Cranky was introduced before Dixie and has been a main stay in the series since then; he's the first character you see when you turn the original DKC game on, and it's implied to be the original DK from the arcade game)