[name_f]Elle[/name_f] is ever such an elegant name to me and I really like it. There’s something about [name_f]Elle[/name_f] with [name_m]Mason[/name_m] that really highlights this quality. [name_f]Eden[/name_f] is earthy and strong and I love the nn option of [name_f]Edie[/name_f]. As a sibset I don’t think [name_m]Mason[/name_m] and [name_f]Eden[/name_f] bring out the best in each other as they rhyme with their two syllables, N endings and long first vowel sounds. However, I think going with the name you think is best for your second child in isolation is more important than how her name sounds alongside her brother’s.
I hope these ramblings help!