It all depends on personal opinion.
Shadow is not a character in Super Smash Bros Brawl, unfortunately.
No, Jack Skellington is not a playable character in Super Smash Bros. Brawl.
What character?
Dark super Sonic is not a character in Super Smash Bros Brawl.
mewtwo is not in super smash bros. brawl however mew is a trophy character
Groudon is in Super Smash Bros. Brawl as a Poke Ballsummon, but not as a playable character.
No, Pichu is not a playable character in Super Smash Bros Brawl
You don't, because the Mii isn't a playable character. The Mii, however, will be a playable character in the next Super Smash Bros. games, Super Smash Bros. for Wii U and Super Smash Bros. for Nintendo 3DS.
Nope. Toad is not a playable character in Super Smash Bros. Brawl. Hope that helps.
Midna is not a playable character in Super Smash Bros Brawl
Pichu is not a playable character in Super Smash Bros. Brawl.
No