Fox is faster than all of them on Temple by a large margin except MK and Sonic.
Also
75m - BANNED. Excessive runaway, overly powerful permanent walkoffs.
Battlefield - STARTER
Bridge of Eldin - BANNED. Extreme MU bias (Falco, Sonic, Pit, among others).
Castle Siege - STARTER
Delfino Plaza - COUNTERPICK. Temporary walkoffs, temporary walls.
Distant Planet - COUNTERPICK. Temporary walkoff, light circle
Final Destination - COUNTERPICK. Moderate MU bias (Ice Climbers, Diddy, others)
Flat Zone 2 - BANNED. Permanent walkoffs, overly powerful hazards, unannounced randomness.
Frigate Orpheon - BANNED. Unannounced random events that can save or remove stocks (platforms on the second transformation)
Green Hill Zone - BANNED. Permanent walkoffs.
Halberd - COUNTERPICK. Announced hazards.
Hanenbow - COUNTERPICK. Moderate circle. Has never conclusively been shown to be too strong for Sonic, which is why it is banned.
Luigi's Mansion - Counterpick/Banned. I'm not sure. The platforms don't really save lives, but in some odd situations they might. Otherwise mild circle that can be weakened by destroying the mansion.
Lylat Cruise - STARTER.
Mario Bros. - BANNED. The game just ends up revolving around using the hazards to your advantage.
Mario Circuit - BANNED. Permanent walkoffs.
Mushroomy Kingdom 1-1 - BANNED. Overly potent walkoffs that are technically temporary but might as well not be.
Mushroomy Kingdom 1-2 - COUNTERPICK. Temporary weak walkoffs, weak walls, mild circle camping, moderate MU bias.
New Pork City - BANNED. Second most potent circle in the game.
Norfair - Counterpick. Announced hazards, moderate MU bias.
PictoChat - BANNED. Unannounced hazards and transformations, including removal of a ledge.
Pirate Ship - COUNTERPICK. Announced hazards, weak blastzone camping, water camping.
Pokémon Stadium 2 - COUNTERPICK. Announced transformations, physics changes.
Port Town Aero Dive - COUNTERPICK. Announced hazards, minor walkoff.
Rumble Falls - COUNTERPICK. Hazards that can't kill, moderate MU bias (characters with poor vertical mobility).
Shadow Moses Island - BANNED. Walls that reward you for breaking them by becoming walkoffs.
Skyworld - Counterpick/Banned. Moderate circle, severe MU bias (Metaknight)
Smashville - STARTER. Random platform starting position isn't really problematic.
Spear Pillar - BANNED. Heavy permanent circle.
Summit - BANNED. Moderate permanent circle.
WarioWare, Inc. - BANNED. Heavy uncontrollable randomness which can completely change the match (invincibility WTF Sakurai?).
Yoshi's Island (Brawl) - Banned. Support ghosts and shy guys can save and remove stocks.
Big Blue - Counterpick/Banned. Moderate temporary circles. Excessive runaway. Badly hurts characters who suffer from RCO lag (which is admittedly a character weakness, but it hurts them more so than any other stage)
Brinstar - COUNTERPICK. Semi-random hazard, severe MU bias (Metaknight)
Corneria - BANNED. Permanent wall. A shame. Also semi-random hazards.
Green Greens - BANNED. Temporary walls, exploding apples (which admittedly are announced but so incredibly rare it's not practical to assume they'll appear).
Jungle Japes - Non-random hazards, weak circle, weak water camping.
Onett - BANNED. Permanent walls and walkoffs.
Pokémon Stadium - COUNTERPICK. Temporary walls, temporary circle, announced randomness.
Rainbow Cruise - STARTER.
Temple - BANNED. Strongest circle in the game, permanent walls.
Yoshi's Island - STARTER. Permanent walkoff, but it's a slope and Dedede needs UNBUFFERABLE FRAME PERFECT TIMING to CG people up it.
So that's
Starter
* Battlefield
* Castle Siege
* Smashville
* Rainbow Cruise
* Yoshi's Island Melee
Counterpick
* Delfino Plaza
* Distant Planet
* Final Destination
* Halberd
* Hanenbow
* Lylat Cruise
* Mushroomy Kingdom 1-2
* Norfair
* Pirate Ship
* Pokémon Stadium
* Pokémon Stadium 2
* Port Town Aero Dive
* Rumble Falls
* Brinstar
* Jungle Japes
With 2 stage bans.