I think we're all aren't looking right at this, and are assuming that every character involved would be playable as opposed to an assist trophy. Let's analyze the other items on the list that haven't yet been discussed.
BMB entertainment is responsible for developing Taiko Drum Master: Appare Sandaime. I can not find any more information relating to this company. Paon is responsible for developing the newer DK games after rare left the equation (perhaps leading to items, AT's or bosses associated with the last couple of DK games, it's maybe an implication of use of DK's and Diddy's final smashes as well. Intelligent also implies items associated with paper mario. There's potentially a lot that's explained by this leak, who knows what it means though. Banjo and necrid could easily be AT's or playable characters.Paon, is resposible for producing a number of series, most famous of which is dragon quest. Also, the inclusion of square enix is promising, notice that it's square enix, and not square enix/nintendo. That could mean sora and not just geno as is commonly expected. Also, notice that camelot, producer of golden sun is not listed. The lack of ape inc implies that ness is not in the game, as they produced earthbound.
Who knows if this is real, but enjoy the slew of speculation.
