I prefer [name_m]Callen[/name_m] (though I would possibly use a different biblical middle like [name_m]Jude[/name_m] [name_f][/name_f]- just to reduce the L count in the name). I like that it gives you [name_m]Cal[/name_m] as a nn too.
[name_f][/name_f]A midway option is [name_m]Caelan[/name_m] (“Kaylin”) which has the [name_f]Kay[/name_f] sound of [name_m]Caleb[/name_m] but that softer, Celtic feel overall.