So, here's a thought experiment...
From the soundtrack, cut down each Stage to having only two of its songs, the ones you consider the most necessary and representative.
I'll have to think this over first...for Duck Hunt I know I'd go with the Duck Hunt Medley, and Swan Lesson. Fucking love that song.
Interesting idea, I'll just do it for a few stages, mostly the new ones.
Mushroom Kingdom U
- NSMBU Overworld (ideally this would have an actual remix)
- Ground Theme/Underground (obligatory 1-1, but it's a good mix)
Mario Galaxy
- Super Mario Galaxy
- Fated Battle
Covers both SMG games with tracks that hit grand space adventure and bombastic boss battle
Mario Circuit
- Mario Kart Stadium (similar to the MK8 circuit theme but more suited to fighting I feel)
- Cloudtop Cruise
Jungle Hijinx
- DKCR Vocal theme
- Gear Getaway
Kongo Jungle 64
- Begrudgingly saying any DK Island Swing mix, preferably the best one (that'd be Swinger Flinger by the way)
- Stickerbush Symphony (fan favourite, retro track for retro stage, fits well, Gangplank Galleon works for an alternative choice)
Skyloft
- Ballad of the Goddess (original)
- Great Sea/Menu Select (to give Toon Link something to fight to seeing as he has no stage for WW)
Pyrosphere
- Nemesis Ridley (Other M)
- Title Metroid
Great Cave Offensive
- Great Cave Offensive medley
- Butter Building V2 (greatly prefer the Brawl version but oh well)
Halberd
- Meta Knight's Revenge
- King Dedede's theme
Covers the other two playable characters with their own themes since the jaunt in GCO don't exactly fit Meta Knight, either choice of Dedede track is fine
Orbital Gate
- Space Battleground (the same track as the stage had in Assault)
- Theme from Area 6/Missile Slipstream
Lylat Cruise
- Star Wolf Assault (RIP Wolf)
- Space Armada or Corneria Brawl
Kalos Pokemon League
- Champion Battle X/Y
- Route 10
Tough choice here, most remixes aren't for X/Y, just went with Route 10 since it's rad and different
Onett
- Onett/Winters
- Either of the Melee themes
Magicant already covers the other two new remixes so might as well throw in the smash staple track in slot 2, I guess Bein' Friends of whatever it's actually called has priority over Pollyana, farewell Love Theme, you will be greatly missed.
Okay you get the idea of what angle I'm going for based on these limitations, I like to use the tracks that better represent the stage itself or the game it comes from while not retreading the same ground like every DK stage does. Though this does mean ignoring some of my preferred remixes for ones I don't like as much.
Also thinking that with music limitations it's nice to have a track that can work for each character on the roster if possible.