I haven’t actually considered [name]Thea[/name] before…kinda like it!
[name]Marin[/name] - I did not realize until clicking on this one that it’s pronounced ma-[name]RIN[/name]. I think she would end up dealing with a lifetime of [name]MARE[/name]-in unfortunately.
[name]Garnet[/name] - Definitely a harsher sound than [name]Willow[/name] and [name]Veda[/name], but I can see the appeal
[name]Tamsin[/name] - A lovely name. I have a negative association though, the bitchy blonde Valkyrie from Lost Girl
[name]Elidi[/name] - love this one, especially the meaning! I think she’d be perfect with [name]Willow[/name] and [name]Veda[/name], and your previous mention of [name]Elidi[/name] [name]Raine[/name] is to die for!
[name]Artis[/name] - I do feel as if it’s a contraction of [name]Artemis[/name]. Either that or a boys’ name, like a mashup of [name]Artie[/name] and [name]Otis[/name]
[name]Salome[/name] - [name]Love[/name], and she has the same softly exotic vibe as your daughters’ names. I do agree with PP that if you use [name]Salome[/name] you’ll be ruling out [name]Solomon[/name] for any future surprise boyos. However, if your last baby IS a girl and you love the sound of [name]Solomon[/name], [name]Salome[/name] could be a lovely choice.
[name]Thora[/name] - I like the idea of [name]Thea[/name]…[name]Thora[/name] is okay. I think I have enough of a feminist streak that I prefer straight-up goddess names to feminizations of god names. [name]Freya[/name], [name]Isis[/name], [name]Demeter[/name], Seshat, [name]Ceres[/name], [name]Eos[/name], Airmid, [name]Rhea[/name], Yemaya, [name]Selene[/name], [name]Themis[/name], [name]Pele[/name], [name]Gaia[/name], and [name]Danu[/name] are some examples of exotic but non-frilly goddess names that could work in your sibset (oh, and there’s Siv/Sif, the wife of [name]Thor[/name])
[name]Bethan[/name] - I do feel like this will be mistaken for [name]Beth[/name] [name]Ann[/name] or a [name]Bethany[/name] typo…I’m sorry! It’s a lovely name…
[name]Tressa[/name] - Another like for your third daughter, and the similarity to “tresses” makes me think of [name]Rapunzel[/name] like plaits
[name]Raine[/name] - Quite possibly my favorite from your list, whether as a middle or a first. [name]Love[/name] that it honors family, and [name]Willow[/name], [name]Veda[/name], and [name]Raine[/name] is an amazing sibset with a cooling, tranquil, zen vibe.
Some more suggestions:
[name]Lotus[/name]
[name]Isla[/name]
[name]Chandra[/name]
[name]Sarai[/name]
[name]Tara[/name]
[name]Petra[/name]
[name]Olive[/name]
[name]Shifra[/name]
[name]Hero[/name]
Cherith
[name]Tahlia[/name] (love the meaning…dew from heaven!)
[name]Circe[/name]
[name]Aura[/name]
Eirlys
[name]Laurel[/name] (and/or [name]Daphne[/name])
[name]Charity[/name]
[name]Ember[/name]
[name]Phoebe[/name]
Tanvi
[name]Sage[/name]
[name]Keturah[/name]
[name]Miko[/name]
[name]Noelani[/name] (I know it’s long, but I love the meaning: beautiful one from heaven)
Aeris
[name]Samira[/name] (literally: one who narrates stories in the night)
[name]Echo[/name]
Ayperi (moon fairy)
[name]Enya[/name]
[name]Saffi[/name] (wisdom)
[name]Kismet[/name]
Awesome list sleepysessha! I love the mention of [name]Gaia[/name], it’s on my long list!
I like [name]Sarai[/name], [name]Petra[/name], [name]Olive[/name], [name]Laurel[/name], and [name]Samira[/name] (I love the meaning)!
I love your daughters names! And I think you have a great list so far my favourites on there are [name]Marin[/name] and [name]Tressa[/name]. I would say [name]Bethan[/name] (my name is [name]Bethan[/name], and that would be very biased haha)
But just to let you know I’ve never been mistaken for a [name]Beth[/name]-[name]Ann[/name], but where I live [name]Bethan[/name] is a known name and only recently double names like [name]Lola[/name]-[name]May[/name], [name]Ella[/name]-[name]Jo[/name] and [name]Cari[/name]-[name]Ann[/name] have become popular. So no one would have suspected it would be [name]Beth[/name]-[name]Ann[/name].
Here are a few names that I think would go great with your girls’ names:
[name]Marina[/name]
[name]Ariana[/name]
[name]Petra[/name]
[name]Thea[/name]
[name]Piper[/name]
[name]Juno[/name]
Enfys (it means rainbow in welsh En-Viss)
Ailsa
[name]Tabitha[/name]
[name]Greta[/name]
[name]Freya[/name]
[name]Harmony[/name]
[name]Lowri[/name] (this is my middle name it means [name]Laurel[/name] and I saw you like the name laurel)
[name]Orla[/name]
[name]Elsa[/name]
I actually wouldn’t usually like [name]Raine[/name] but I think it fits perfectly with your girls names and has such a nice family connection, it would be my pick. I also think [name]Tamsin[/name] and [name]Tressa[/name] are lovely. [name]How[/name] do you pronounce [name]Elidi[/name]?
Beautiful list!
My favorites are [name]Garnet[/name] and [name]Tressa[/name].
[name]Garnet[/name] is nice with [name]Willow[/name] and [name]Veda[/name] because it’s similarly literal but evocative and a tiny bit shadowy (unlike straightforward [name]Ruby[/name])
I usually sniff at those names that refer to birth order, but [name]Tressa[/name] is magical. Three is a powerful number anyway.
I want to like [name]Elidi[/name] more than I do, because it’s great written and fresh as can be. To my ears though, it’s too close to [name]Melody[/name]. Prefer [name]Alida[/name].
[name]Salome[/name] and [name]Solomon[/name] would be incredible for G/B twins.
[name]Artis[/name] and [name]Raine[/name] are divine, as firsts or middles for [name]Tressa[/name] - neither goes with [name]Garnet[/name], sadly.
Other [name]Arthur[/name]-related names-
[name]Artemis[/name]
[name]Artemisia[/name]
[name]Aretha[/name] 
Also, maybe its not dry enough for you, but [name]Lilith[/name] springs to mind.
Bethlow- thanks for the input. In [name]Canada[/name] (in the 70’s/80’s) [name]Beth[/name]-[name]Anne[/name]/[name]BethAnn[/name] was pretty common, and I don’t think I’d want to correct people all the time. I love [name]Freya[/name]! Hubby says he likes it too. I worry it might be too close to [name]Veda[/name] (“vay-dah”), though.
[name]Maudie[/name]- [name]Elidi[/name] is pronounced “[name]Ell[/name]-id-ee”
Emmabobemma- hubby dislike [name]Elidi[/name], “because it just sounds like you’re saying [name]Melody[/name] wrong!”