[Under the Mask: Clues and Clue Discussion]

Butterfly - Ellie Goulding without a doubt in my mind!

Skeleton - Paul Schaeffer

Thingamajig - Victor Olidepo

Ladybug - Kelly Osborn

[S02.E01: Return of the Masks, Groups A&B]

I think that Butterfly is Ellie Goulding, she did a cover of Take me to Church on her YouTube (Amen also) and she's from England.