While it was only just last week where Masahiro Sakurai confirmed Super Smash Bros. Ultimate would indeed have 5 DLC fighters that doesn’t included the Piranha Plant, it was never stated who the 5 fighters will be.
Naturally, the fan base went made with their predictions and hopes, but yesterday, Sakurai has gone ahead to reveal that although the 5 characters aren’t being developed yet, as their development will start just as soon as the team is finished with the main game, Sakurai has confirmed the line-up is decided already.
He also said Nintendo decided the line-up, but he did have final say. For his exact wording, feel free to consult his English tweets below:
Super Smash Bros. Ultimate’s DLC line-up is now complete. This time the selection was made entirely by Nintendo. I decide if we can create a fighter based on their selection, then come up with the plan.
— 桜井 政博 / Masahiro Sakurai (@Sora_Sakurai) November 6, 2018
It’s great to dream about your favorite character joining the battle and I appreciate your passion, but please try to stay on topic when replying to tweets and refrain from flooding us, and other users, with requests when we're not specifically asking for feedback. Thank you!
— 桜井 政博 / Masahiro Sakurai (@Sora_Sakurai) November 7, 2018
So there you have it, the new fighters are already decided upon and now it is just a waiting game to find out who and what, those fighters will be. The time for begging, is over.
Source: @Sora_Sakurai (Twitter)