I still think there are a few more secret characters but I would likely play these first

Donkey Kong also known as DK
Bowser also known as King Koopa or Koopa
King Dedede
Ganondorf I don't know if he is a clone yet
Kirby he's so cute
Yoshi he was super strong in Melee
Peach best to be if you are a coward
Zelda/Sheik I need to see her Final Smash
Metaknight he looks cool
Pit the only angel in the game
Diddy Kong well he got his peanut gun

That are the ones I'm most interested in that list I will also play as the others to.

Level Editor. I think I'll oddly have the most fun making wackey stages and have the CPU fight each other in them.

Aside from that....

Kid Icarus
Metaknight
Rob
Luigi
Sheik

Link
Young Link
Olimar
Wario

So sad .... really wanted mewtwo in the game anyways ...

Link
Ike
Sonic
Pokemon Trainer

^ you could try Lucario

Lucario, Ganonforf.

Newcomers;
Metaknight (played as him for a little bit at E for All)
Sonic (already played as him at E for All a ton)
Olimar
Pit (played as him for a little bit at E for All)
Toon Link

Veterans:
Ness (pray he can still Double Jump Cancel)
Jigglypuff

Marth (my Melee main)
Sonic
ZSS
Pit
MetaKnight

Yoshi yoshi and yoshi

Jiggles, Jiggles and more Jiggles!

Then I will definitely need to check out how Pit and ROB work because they seem like they could be very interesting. I hope that Pit proves to be really good because I think he could become another one of my mains. My mains in Melee were Jiggles and Peach so I like the floaty characters best.

Those complaining about anything in this game disgust me. This will be the most perfect game to grace the face of the earth.