It's all very subjective, but I am not keen on frilly names for girls. Lilyanna and Ariella do sound frilly independently. When they are a pair, that seems to overemphasise the frilliness iyswim.
Xavier is such a cool name, it seems a shame to me to give his sisters frilly rather than cool names and, rightly or wrongly, it does make me think why does the boy get to be cool but the girls have to be... French fancies?