On that music thing, considering the following for music total (under the assumption that all the tracks in the sound test are the final count):
Castlevania has 34, Metroid has 25, Yoshi has 14, Kirby has 39, Star Fox has 17, Game & Watch has 2, Wii Fit has 10, Sonic has 20, Bayonetta has 11, FFVII has 2, Street Fighter has 36, Pac-Man has 13, and the other section has 97. Moray Towers was shown to have 23 tracks available for selection, but we don't really know if
all of them are from Splatoon. However, for now, let's assume they are.
All of that adds up to 343 tracks.
That leaves track totals from Smash itself, Mario, DK, Zelda, Pokemon, F-Zero, Earthbound, Fire Emblem, Kid Icarus, Wario, Pikmin, Animal Crossing, Punch Out, Xenoblade, Metal Gear, and Mega Man unaccounted for.
It's been stated in this
interview that Mega Man and Fire Emblem also received a substantial increase in tracks, the music team has more free reign in picking songs, some tracks get stuck in licensing hell, and that there won't be as many mellow songs this time (like The Roost).
Either some series' just have a ton of music (Mario having a lot wouldn't be a surprise; it did have 71 in Smash 4 alone) or there might be other franchises involved. Hm.