Complete the indicated task to unlock the corresponding costumes.

Momiji's third costume: Complete 25 Ninja Trials with Momiji.
Momiji's fourth costume: Complete 50 Ninja Trials total with Momiji.
Ryu and Ayane's third costumes: Collect all 50 Scarabs.
Ryu and Ayane's fourth costumes: Collect all 10 Crystal Skulls.