I’ll pitch a few names to you 
bolded my favorites!
[name_f]Zillah[/name_f] - I adore [name_f]Zillah[/name_f] for you- she’s obscure and biblical, and she’s got that hippy/boho flair that E’s name has. Also, I think the meaning ‘shade’ is a sweet tie in to E’s tree name
[name_f]Kalila[/name_f] - She’s offbeat and lyrical, with a sweet meaning. also, i love the nn “lila” with you–wynn and lila are so sweet together!
[name_f]Marigold[/name_f] - An earthy, and bright nature name (with soooo much nn potential). Also, Marigolds’ connection to remembrance feels like a special nod to your angels. I especially love her as a middle for you!
[name_f]Aviva[/name_f] - I’ve loved her with E’s name since you mentioned her recently! She’s so lovely and zippy, and with such a poetic meaning.
[name_m]Joah[/name_m] - An earthy, offbeat alternative to [name_m]Noah[/name_m]. I can easily see him on your list!
[name_f]Havilah[/name_f] - An obscure, biblical place name, but with the same earthy, whimsical edge that El0wyn has–she ticks all the boxes!
[name_f]Adah[/name_f] - A lovely, solid biblical name. I think the -h spelling (as opposed to [name_f]Ada[/name_f]) gives her a wonderfully folksy flair.
[name_f]Avielle[/name_f] - She’s got a biblical meaning, and a spiritual, mountainous sound. El0wyn and [name_f]Avielle[/name_f] are so perfectly well-balanced, but not too matchy (AND she completes your ‘wreath’)
[name_f]Solstice[/name_f] - I love this for either gender, but especially on a boy for you, he’s so gently folksy and earthy. [name_m]The[/name_m] [name_f]Solstice[/name_f] signifies a time of new beginnings and abundance, which is so perfect for you!
[name_m]Zimri[/name_m] - He’s spunky, and zippy, and I adore the musical meaning! Plus, he’s got loads of biblical connections. [name_m]Zimri[/name_m] and El0wyn sound so lyrical together!
[name_f]Attalia[/name_f] - Obscure biblical place name, with a gorgeous, soft sound. [name_m]Her[/name_m] similarity to [name_f]Adalyn[/name_f], [name_f]Adelaide[/name_f] etc makes her feel so useable as a name! Also, nn atty/attie is tooo sweet!
[name_f]Zorah[/name_f] - [name_f]Gorgeous[/name_f] biblical place name, with a bubby sound. [name_f]She[/name_f] feels like an edgier [name_f]Norah[/name_f], which I love for you!