Successfully complete the indicated task to unlock the corresponding:
Blockafeller: Find Sprout in all 43 of his hiding spots.
Kamek: Successfully complete all courses in the game, includes postgame courses.
Sundream Stone: Collect all Smiley Flowers in the game, then give all your remaining flowers to the Blockafeller outside of Kamek's hideout.
Scan the indicated amiibo into the game to unlock the corresponding costume:
Amiibo Box: Scan any non-compatable amiibo.
Blue Yarn Yoshi: Scan the Blue Yarn Yoshi amiibo.
Bowser: Scan any Bowser amiibo.
Green Yarn Yoshi: Scan either the Green Yarn Yoshi or Mega Yarn Yoshi amiibo.
Koopa Troopa: Scan the Koopa Troopa amiibo.
Luigi: Scan any Luigi amiibo.
Mario: Scan any Mario amiibo.
Peach: Scan any Peach amiibo.
Pink Yarn Yoshi: Scan the Pink Yarn Yoshi amiibo.
Toad: Scan the Toad amiibo.
Yarn Poochy: Scan the Yarn Poochy amiibo.
Yoshi: Scan any plastic Yoshi amiibo.