I'm having the same issue...

Brynlee Morrison for the first stage I used a large portion of the jellyfish set, and that worked for an S.
Hair: Watery-Rare
Dress: Princess Jellyfish
Coat: Jellyfish-Rare
Hosiery: Foam-Rare
Shoes: Ice Roses
Accessories: Pigeon Maid, Jellyfish Glow-Rare, Sapphire Sea-Rare, Snow Diamond Chain, Snow Diamond Bracelet, Oceanic, Wind Wave-Rare, Timely Bloom, Red Satin-Rare

For the second stage I used kimono-tagged items for the most part. I got an S
Hair: Geisha-Rare
Dress: Aster
Coat: Higanbana-Rare
Hosiery: Fallen Flower
Shoes: Firelight
Accessories: Fox Mask, Fish Love, Japanese Fan-Lady

I haven't gotten more than a B on the third, either...