While Baseball, Horse Racing, and Soccer evenly divide the sixteen default characters into four different categories, tennis does not do so.
Mario, Luigi, and Daisy are Balance types.
Peach and Baby Luigi are Technique types.
Yoshi, Birdo, Baby Mario, and Diddy Kong are Speed types.
Waluigi is a Defense type.
Donkey Kong, Wario, and Bowser are Power types.
Boo, Bowser Jr, and Rosalina are Tricky types.
Daisy is still a Technique character for Baseball, Horse Racing, and Soccer. Golf doesn't use character types but Daisy's trajectory is Draw.
This video shows the character types for tennis: https://www.youtube.com/watch?v=P-efGnTdcZ4