Super Smash Bros. Characters by First Letter

For characters whose alternate costumes are represented by different characters, those characters are acceptable

Hint: An alternate costume for O***** is currently the only character in the game whose name begins with the letter A. Likewise, an alternate costume for S**** is the only character whose name begins with E

Each of P****** T******'s Pokémon is acceptable

Sans is not an answer, he's just here. Hi, Sans :)