Black Outfit

[Keyblademastar]

Well Namine is capable of opening corridors without a black cloak.

 

[Ultima Scorpio]

I think you are looking too far into it. There outfits aren't THAT similiar.

I dunno though.

 

[Zook]

I'd think they had got their outfits from the same fairies since Yen Sid was Mickey's mentor

 

[Garth]

Maybe there is no significance at all. Maybe there is so much significance, it's impossible for us to comprehend it.

Maybe, right now, Nomura is reading this board, laughing himself into a coma.

.....or, yeah. Maybe they got them from the same fairies, too. D:

 

[Antiquity]

Mickey was supposed to be the main character for the KH series, but it was changed to Sora instead. Maybe since they have some similarties (strong sense of justice, etc.), it makes sense that they have some sort of connection through clothes. *shrugs* I dunno, they're just clothes.

 

[Garth]

I dunno, they're just clothes.

My thoughts exactly. :|

Although, if they do have some significance, it'd be quite enjoyable to know what it is.

 

[Vairocanum]

The simplest thing I can say about it is that it's a proof of being a member of The XIII Order. Back then before we actually knew the Order existed (KH1FM Secret Ending, Deep Dive), Mickey, Riku and Roxas was labeled as the "unnumbered". Maybe that's the case, as camouflage? 'Cause if you think about it, isn't it weird that the Order don't give a damn to whatever Mickey and Riku is doing? If Sora just lazed around in KH2, I bet they would still say something like, "lookout! He's scheming/plotting something!", while Mickey was trying to find a way to contain Kingdom Hearts.
Correction is welcome.

 

[Soldier Terra]

What if mickey can drive in BbS? LOL

 

[Vairocanum]

Well... It's actually pretty old debating about this seeing that the XIII Order is gone hahaha.