Bumping the hell out of this thread because Smash 4 for 3DS/Wii U includes a bunch of Melee reprises... with arranger credits:
Hirokazu Ando:
Battle Theme (Pokémon G/S), Big Blue, Corneria*,
EarthBound (Fourside)**, Green Greens, Kongo Jungle (DK Rap), Mach Rider,
Mother 2 (Pollyanna), Poké Floats, Saria's Theme**, Yoshi's Island, Yoshi's Story
Tadashi Ikegami: Fountain of Dreams, Venom
Takuto Kitsuta: Great Bay, Mute City
Shogo Sakai: Brinstar*, Brinstar Depths*, Dr. Mario*, Fire Emblem*, Hyrule Temple*, Icicle Mountain, Jungle Japes**,
Mother (Onett),
Pokémon Stadium (Pokémon R/B), Princess Peach's Castle, Rainbow Cruise*, Super Mario Bros. 3
Starred* songs are in both the 3DS and Wii U versions, unstarred are only in the Wii U version.
Double starred** songs are in Smash Ultimate.
Also confirms Ando composed Flat Zone, which we knew already.
EDIT: There are 4 unlockable tunes I left off initially and just added: Battle Theme, Icicle Mountain, Poké Floats, and Pokémon Stadium.