Do the following achievements to unlock the characters and to get bonuses:
Flower Cup: finish the Normal Mushroom Cup to unlock the Flower Cup.
Rainbow Cup: finish the Normal Star Cup to unlock the Rainbow Cup.
Star Cup: finish the Normal Flower Cup to unlock the Star Cup.
Gira Gira Desert stage: Win by 800 points in the Normal Star Cup to unlock the Gira Gira Desert stage.
Moogle Garden stage: Dunk three times on the Daisy Garden court in the Flower Cup. A panel should appear.
Sunset Beach stage: play at Noko Noko Beach between 4:00 and 6:00 p.m. in Exhibition mode.
Birdo: finish the Hard Mushroom Cup with a "Bronze" rank to unlock Birdo.
Black Mage: finish the Normal Rainbow Cup with a "Gold" rank to unlock Black Mage.
Boo: finish the Hard Flower Cup with a "Bronze" rank to unlock Boo.
Bowser: finish the Normal Star Cup to unlock Bowser.
Cactuar: play in the Desert stage in Exhibition mode.
Dixie Kong: finish the Normal Flower Cup with a "Bronze" rank to unlock Dixie Kong. Flyguy: finish the Hard Star Cup with a "Bronze" rank to unlock Flyguy.
Moogle: finish the Normal Star Cup with a "Silver" rank to unlock Moogle.
Ninja: finish the Normal Rainbow Cup to unlock Ninja.
Paratroopa: finish the Normal Mushroom Cup with a "Bronze" rank to unlock Paratroopa.
White Mage: finish the Normal Rainbow Cup with a "Silver" rank to unlock White Mage.
Use the following tips to get alternate costumes. You have to get the indicated Cup and then hold Up, Down, Left, or Right while moving the appropriate character into the basketball ring:
Daisy: Normal Flower Cup with a "Silver" rank
Flyguy: Hard Star Cup with a "Silver" rank
Ninja: Hard Rainbow Cup with a "Silver" rank
Black Mage: Hard Rainbow Cup with a "Bronze" rank
Peach: Normal Mushroom Cup with a "Silver" rank
White Mage: Hard Rainbow Cup with a "Gold" rank
Yoshi: Hard Flower Cup with a "Silver" rank
Complete the indicated task to unlock the corresponding basketball bonuses:
All Silver: finish the Dribbling challenges.
Blue And Silver: finish Training mode.
Cheep-Cheep: get a "Gold" rank in the Mushroom Cup in the Hard Tournament.
Dice: get a "Gold" rank in the Flower Cup in the Hard Tournament.
Gold: get 5,000 points in your profile
Goomba: get a "Gold" rank in the Star Cup in the Hard Tournament.
Soccer: get a "Silver" rank in the Mushroom Cup in the Hard tournament.
Star: get a "Gold" rank in the Star Cup.
Watermelon: get a "Gold" rank in the Flower Cup.
Yoshi Egg: get a "Gold" rank in the Mushroom Cup.