The Mei & Natsumi Character Pack Add-on for 100% Orange Juice has 6 achievements.
Play 10 games as Mei (DLC 18)
As Mei, KO at least 5 people in 1 match in combat while having Red & Blue in hand (DLC 18)
As Mei, KO at least 2 units with one White Christsmasher or True White Christsmasher (DLC 18)
Play 10 games as Natsumi (DLC 18)
As Natsumi, heal 10 or more HP with one Cooking Time (DLC 18)
As Natsumi, heal 10 or more HP in one game by cooking for people on the same panel. (DLC 18)