Here are my probabilities:
(1)Mario, (2)Link, (3)Pikachu, and (4)Kirby - Confirmed; 100%
(5)Donkey Kong, (6)Fox, (7)Yoshi, (8)Luigi, (9)Jigglypuff, (10)Ness, (11)Samus (suited), and (12)Captian Falcon - Nothing less than 95% (They wouldn't split up the original Smash fighters...would they?)
(13)Falco, (14)Y. Link, and (15) Ganondorf - 90% (Of all six clones, these ones have the greatest chance of returning with a new(er) moveset.)
(16)Zelda/(17)Shiek - 85% (Preferably as two seperate characters.)
(18)Marth - 85% (Fire Emblem needs a represenative and who better than the third top tier of Melee?)
(19)Peach - 85% (She has decent moves. She has a large fanbase. She is fourth in the tier list... She's in.)
(20)Bowser and (21)Mewtwo - 80% (Link gets his villian and Kirby gets his...why not the top two most selling game characters in history? I also see Fox gaining one of three possible villians [Wolf, Andrew, or Scales] as well as one of his sidekicks [Skippy or Krystal.])
(22)Ice Climbers and (23) Mr. G&W - 50% (They provide a bit of history about Nintendo; they (along with Ness) mix old scholl with new school.)
(24)Roy, (25)Pichu, and (26)Dr. Mario - Less than 25% (These three characters were really nothing but fillers. Sakurai said himself that they had a hard time finding the right characters... If anyone goes, these three are first on the list.)