I think [name_u]Mackenzie[/name_u], [name_u]Madison[/name_u] and [name_f]Kylee[/name_f] are a similar style, to me they have a late-90s popular feel. They might go with [name_f]April[/name_f], but they don’t really fit with some of the other names, which are more unusual nature type names. I almost see two sets, with those 4 together and another set with [name_f]Luna[/name_f], Amore, [name_f]Persephone[/name_f] and [name_u]River[/name_u].
[name_f]Luna[/name_f] and [name_f]Persephone[/name_f] - MYTHOLOGICAL
[name_u]Madison[/name_u] and [name_f]Kylee[/name_f] - CONTEMPORARY ([name_u]Mackenzie[/name_u] would be included in this group but it is too similar in sound to both [name_u]Madison[/name_u] and [name_f]Kylee[/name_f]).
[name_f]April[/name_f] and [name_u]River[/name_u] (and Amour - if you don’t mind two sharing the same initials) - WORDS