I wonder if shards are keept to when this event returns.

Each pudding/burger gave me 3*5 = 15 shards.
If a player have saved 40 puddings for this event and spends the 10 burgers he earned at this event he should already be half way to unlock the 3 girls.
Anyway around 500 free players and maybe 100 p2w got all girls so not a super hard event.

Osawari Island event is much harder...