There aren't many match ups that aren't heavily skewed in Meta Knight's favour on those stages.
MK's
"Even Match Ups"
Snake
Diddy
Falco
Wario
*list of stages*
]
when CP, the loser says the stage and then the winner can change character to avoid getting his character ***** in a bad stage for him. So if Mk cps you whichever of this stages you still have options of getting and even or close to even match-up
exemples:
Rainbow Cruise
->Wario
->Kirby
-> Falco ( has an infinite on this stage that can pwn MK)
-> DDD ( not sure if even or small disadvantadge)
->G&W/Yoshi/Jiggs small disadvantadge (4-6?)
Norfair
->Wario ***** at norfair.
-> if planking wins, Jiggs/G&W win too.
-> lol Deva beat DSF with link here ( of course Link is ***** by mk in any stage, but just saying to point mk isn't invencible in this stage)
Delfino Plaza
-> Snake, Diddy and Wario can still do well in here
-> Kirby/ Jigglypuff/Yoshi can compete against MK here (4-6)
-> DDD is either even or small disadvantadge
Lylat Cruise
->Wario is awesome in this stage
->why is this an especially bad stage for snake/diddy?
->Falco can still do well here, he would be at a close disadvantadge
->Kirby/Jiggs/Yoshi/DDD/DK/Bowser are able to compete with MK (4-6)
Frigate Orpheon
->Snake and Wario do pretty well here
->Kirby, Jigglypuff and DDD can fight MK here too (4-6?)
Luigi's Mansion:
->First off this stage should be banned.
->Olimar does awesome in here
-> as you said Snake can defeat MK here
->The other caracters I've said somewhere in this post can still do acceptable here except Diddy and Falco
there ya have plenty of options of how to have a chance of winning in a MK counterpick
of course this isn't for scrubs who think 6-4 are impossible match-ups or that just think MK is unbeatable.
I don't see how MK is auto-win in any of these stages, and don't forget there's the ban stage rule so you can ban the one you play worse on. and some tourneys don't even have norfair or Luigi's as cp stages