Kinda don't mind the addition of this new character to add to the mystery of Clover's identity and Uichi's bullying, because rather than like "be a new plot point just to solve the mystery" it kinda makes sense if this girl was the true Clover or maybe one of their pawns because Clover or their main pawn seems associated with twisted smiles which previous candidate Rei is never shown to do. Rei is only shown to have hateful and depressed expressions. Plus back when we see Yae's backstory, the shadow Clover seems associated with appears behind him... despite Yae seeing Rei in front of him, as if the real Clover was literally behind him at the time.
