I like that roster. It feels quirky and definitely very Sakurai, though I would be sad without the inclusion of Mewtwo. Maybe one of those random slots would fill in for him instead.
Here's what I'm going with right now:
In this roster it's 48, 4 cuts JUST in case thats true (it seems likely to me anyway so why not go with it) and I added all of Sal's leaked newcomers.
Ivysaur and squirtle count as 2 cuts and Snake being cut makes 3, decided to cut Ike and add Mewtwo so that none of the series go "down" in number of "reps" (pokemon 6 /fire emblem 2). Mewtwo makes sense because, since hes a veteran, similar to reworked Charizard
for pokemon trainer, Sal's leaker friend didnt see him as a "newcomer" and thus not leaked.
Ridley's been super hinted about and teased and I could see even sals leaker friend keeping him under wraps so I threw him back in...theres just too much mystery there for me to deconfirm him, it FEELS like hes being teased at us, plus it fits the trophies = characters theory.
to fit the "trophies in the direct = new characters" theory, Ganondorf is reworked (again similar to pkmn trainer becoming charizard) uses a sword now or something and is seen as semi-"new" and thus fits the zelda trophy spot. palutena fits the kid icarus trophy, chrom fits the fire emblem trophy, and ridley fits the metroid trophy.
now on to Mii's, I think Mii's wont "count" as a character spot. Something like they are only selectable in the custom move set mode OR not playable online or something and it will be more of a novelty "mode" than a character and thus the "roster" is still 48 spots. consider Mii's on the selection screen might just be a button on the side to select them or whatever and if someone saw the number of characters and leaked it (48) they didnt count the mii and random button or something.
So this roster fits (by jumping through a lot of hoops) all the stuff thats been leaked /hinted at/talked about lately: Sal's 2 leaks, The trophies being characters, and the 48 characters 4 cuts (i know its "disproven" but im using it as limitations in case it turns out to be true, again probably close to what we'll get anyway so im going with it).