Wierd question.... but the answer would just be an opinion.
No, Pichu is not a playable character in Super Smash Bros Brawl
Shadow is not a character in Super Smash Bros Brawl, unfortunately.
Midna is not a playable character in Super Smash Bros Brawl
What character?
No, Jack Skellington is not a playable character in Super Smash Bros. Brawl.
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.
There is not playable character called Jet in Super Smash Bros Brawl.
Nope. Toad is not a playable character in Super Smash Bros. Brawl. Hope that helps.
No
Mewtwo is not a character in Brawl