Limited information is avaliable at current but will be updated as soon as more is learnt about it.
Sharlene was a student from Malfield school which came for the Chess Tournament held at Pinkerton. She only makes her appearance in Episode 19 so not much else is known about her.
Her appearance is similar to Trixie's with the exception of her hairstyle, blue clothing and eye colour.
She is good at chess and has her own chessboard (The Queens Game)
The voice for Sharlene sounds like Trixie's. May just be the same voice.
A confliction with the fact above because i have no proof to show her voice is Trixie's
Also she was carrying a chessboard for the other fact but it could of been one from Malfield.(The school she attends).