It would still have to be a copycat of the g-idle members or else they're going to have to wipe two champs and replace them in kda. the listeners are going to know when a voice changed too much. Also the KDA concept is that they are supposed to be an international korean group. would be weird to have two songs featuring the korean language strongly then to just flop it.
Didnt they created Seraphine for this for the chinese market? They can reused her again. They made her and kda sang together for the world last year. They can continue her brand being a soloist. Twitter and League players hate Seraphine tho. I never seen a digital character gets so much hate before haha