Do the miis count as "all characters"?

[smashbro29]

On 3DS they didn't, the only reason you'd run through classic or all-star is to get their trophy.

I don't think they do, I beat 10 man Melee in under 25 seconds with everyone, didn't even have mii on my roster.

 

[Mario & Sonic Guy]

Even if you're not required to use the Miis, you'll still have to use them to get their trophies.

 

[Raijinken]

They do not count for any challenge that says "With All Characters," as far as I know (I know this is true for the 3DS and for the lower-level challenges on the Wii U, can't entirely confirm for the higher ones I haven't finished yet). But like Mario_and_Soinc_Guy said, you will have to beat modes with them if you want their trophies.

 

[smashbro29]

Yeah but I could make 3 miis up in 2 seconds, run through easy and 0.0 and call it a day for the trophy.

The less mii involvement the better.

 

[Polearm]

They do not, HOWEVER they will not show up as alts in the shop randomly until you beat all star and/or classic with them.