My "most likely" list happens to match up exactly to the "characters I want" list, but here goes:
- Wolf. Veteran, more relevant than literally any other veteran and most newcomers that could be chosen, first-party, extreme fan demand, and being the most original 'clone' by far (including Luigi) all give him a pretty high likelihood.
- Pichu. Not even trying to joke here - it's not like Smash is in need of more Pokemon reps and all, and most fans pretty senselessly hate Pichu, but think about it: decent fan demand, first party, everyone loves Pichu (jk), room for being made less of a clone through (everyone's favorite/the forgotten) Ukelele Pichu's hilarious BS, and ease of development given a very lightweight low-necessity model and a simple moveset.
from this point on it's really just a list of 'why this character is deconfirmed', starting with the #3,
- Snake. Veteran, relevantish (not even really in MGSV, so...) very high fan demand, but third-party, Konami's being a major shit, and including him would cause a pretty noticable shift in the game's rating - something they removed the Tharja trophy just to avoid, lmao
- Squirtle or Ivysaur (though Ivysaur falls lower). Relevantish through ORAS (it released the same time as one of the Smash versions, but still), high fan demand (higher for Squirtle, obviously), first-party, but was deconfirmed around the time of Zard's release (both by common sense and by Nintendo, iirc) and are kinda on a thread if they haven't ALREADY been put in the game, tbh
- Icies, deconfirmed because the 3DS version exists (don't even start guys) - if they do add them to the game, it'd either be Wii U exclusive or drastically changed to the point of ridiculousness (and if the former case, they'd have to compensate 3DS players such as I somehow).
- characters like Shantae or Shovel Knight who haven't had Japanese releases, IIRC, and aren't made by major companies. This is especially important in Shovel Knight's case, as he spans a single game - Shantae has been around since the GBC, meanwhile, which gives her some time to build up a reputation. Either way, a little screwed.
- characters like Isaac or reps from far down in the bin of classic Nintendo titles that are just too nonrelevant or not popular enough tbh
note that i love and adore literally every named character on this list and i'd love for them all to be in the same smash game all at once as a big happy family but dammit guys