Here are my suggestions:
Olivia &
Ophelia
Q: I don't like any Q names for girls but maybe
Quinn &
Quiana (pronouced Key on uh)
U: I don't like any U names for girls but maybe
Ursella (pronounced ers ella) & Uliana / Ulia (pronounced u lee on uh / u lee uh)
Xylia & Xiana (pronounced z on uh)
Yuliana /
Yulia &
Yasmine /
Yasmin
Zoey &
Zoya (although this is bit close)
Zoey &
Zaria