A member can stay in her position but at least one needs to change positions.
I will place RINA in Bass, I want to see her move around standing and playing the bass like TOMO does.
I also like to see her dance!
I will place TOMO in drums, I want to see her HIGH ENERGY pour on those drums. Hahaha.
As for HARU and MAMI, I like them where they are.