In all honesty I don't expect the likes of King K. Rool or Isaac to get in without the assistance of the Ballot. King K. Rool has mostly been ignored & the last Golden Sun game bombed hard. In my opinion, if we're getting anyone outside of the ballot, it'll either be the Chorus Kids (we know that we were supposed to get a RH rep) or the Inklings (given how much Nintendo's promoting Splatoon). Of course, that last mystery slot (given that Wolf gets the other one) could go to the ballot character with the most votes that's within reason (I.E. originated from a video game, not from a rival console maker, etc.), but I'd be genuinely shocked if the last slot wasn't for either the Inklings, the Chorus Kids, or the winning reasonable ballot character.