this guy on GameFAQs showed a 4chan leak a few weeks ago that adds a whole new definition to fake this is the post
Didn't save the pic, but I remember some of the details the characters will be
Newcomers
K.Rool (has Kaptain as an alt... not Baron K. Roolenstein though)
Geno
Chibi Robo
Elma
Isaac
Ashley
Bandana Dee
Bubbles (Clu Clu Land, Retro Rep)
Echos
Dark Samus (More rapid attacks, forward B is a barrage and not a missle, run animation is flying, most different of the echos still classified as one)
Dixie Kong (revealed in K.Rool's trailer. Her final Smash is "Double Trouble" includes Kiddy Kong, her up b is a Helicopter Pack, but she does use her hair for throws)
Isabelle - She seems very nervous on her harder hitting attacks
Shadow (Only Third Party Newcomer, Ultimate has him use Chaos Control and then use Super Shadow, Sonic's Final Smash but harder to dodge)
Chrom (Joke character)
Black Shadow (Basically, Melee Ganondorf)
January 19th 2019 will have "Dragon King" added in, a character created by Iwata for the original draft of Smash 64 before it was a Nintendo crossover. Alongside Mushroom Kingdom 64, and a stage for Dragon King.
Beyond that
Banjo Kazooie, and he comes with two stages Timber Island (Diddy Kong Racing), and Hailfire Peaks which "Stops" and "Swops" from ice to lava. Downloading him adds both Banjo Kazooie and Diddy Kong Racing trophies to collect.
Timber Island is sadly just a reskinned Isle Delphino, you can see Taj and Wizpig racing around the island in the back ground
Banjo's reveal Trailer focuses heavily on Banjo and Diddy Kong.
Rex and Pyra are DLC
as are Springman and Ribbon Girl
Beyond these no DLC characters are planned. The DLC is reserved for Dragon King (who's a free anniversary gift), and three characters who ordered too late in development to count. If fans demand DLC, there will be more beyond these.
New Stages
Sarsaland - (Will be shown off in a video close to release showing off Echo differences)
Kitchen (Chibi Robo stage)
Dark Aether
Gyromite Lab
Clu Clu Land
The "Character gives advice to related character" (Palutena's Guidance/Snake's Codecs) is both the old ones... Snake for Shadow Moses, Pit for his stage... and.. ROB gets advised by Professor Hector on the Gyromite Lab stage
No not all Newcomers get their own stage...
King K. Rool in Classic uses Pirate Ship
and Isaac gets one of the Fire Emblem stages (which seems weird, but whatever)
Elma just gets Shulk's stage
Simon Belmont is fake, the Minecraft Stage is also fake