Alright, let me try to help you cut down your current list and then I’ll make some suggestions to confuse you even further 
This vs. That:
Boadicea vs. Bradamante: I say this round goes to Boadicea. I prefer her to [name_f]Boudicca[/name_f] and Bradamante is still totally masculine to me (though I know you love her). Perhaps you can use Bradamante as a middle? She goes very well with many of your names, in my opinion.
[name_f]Cleopatra[/name_f] vs. [name_f]Isis[/name_f]: I still say [name_f]Cleo[/name_f]. While I’ve come around to [name_f]Isis[/name_f] and agree she’s a short name that packs a punch, [name_f]Cleo[/name_f] is so dramatic and wonderful that I can’t resist!
[name_f]Cleopatra[/name_f] vs. [name_f]Zenobia[/name_f]: Ooh, tough one. A&Z would be super cute - DitaRoo and ZennaBee! However, I still love [name_f]Cleo[/name_f] so much. I feel like she has a slight edge over [name_f]Zenobia[/name_f] for me.
[name_f]Isis[/name_f] vs. [name_f]Isolde[/name_f]: [name_f]Isolde[/name_f]. [name_f]Isolde[/name_f] all the way. Doesn’t matter though, I’ve already vetoed [name_f]Isis[/name_f] in the [name_f]Cleopatra[/name_f] pairing (I feel like I’m watching a boxing match right now).
Nimue vs. Niniane: I’m still championing (did I just make up a verb?) Nimue. [name_f]Love[/name_f] the ethereal, flowing sound.
[name_f]Guinevere[/name_f] vs. Gwenllian: I think you can probably use [name_f]Guinevere[/name_f] & [name_f]Morgana[/name_f]; while it’s not an ideal sibling pair, I don’t think it’s terrible. And the fact that you say you both love it is encouraging! Of the G’s, I do think I prefer [name_f]Guinevere[/name_f].
Veto with [name_f]Morgana[/name_f] as a sister:
[name_f]Yavanna[/name_f]: I don’t think that they’re exactly alike, but I do think they’re a little too similar to be sisters. [name_m]Say[/name_m] it aloud: [name_f]Aphrodite[/name_f], [name_f]Morgana[/name_f] and [name_f]Yavanna[/name_f]. I feel like [name_f]Dita[/name_f] might be the odd one out.
Bellicent: I did a quick bit of internet research on her, and I agree with Husband that you should veto if you prefer [name_f]Morgana[/name_f]. Also, I’m sorry but I still see a smoosh of [name_f]Belle[/name_f] & [name_f]Millicent[/name_f]. Sorry sorry!
Veto for other reasons:
[name_f]Circe[/name_f]: I agree that she works better in the middle.
Tinuviel: Well, I think that’s a weird thing to worry about, because how on earth can a name be too cute? Haha, but in all honesty I don’t love this one as much as some of your others. I think [name_f]Aphrodite[/name_f] and Tinuviel might be a bit mismatched.
Names still on my list for you:
[name_f]Olympia[/name_f]: Why save her for a future child when you can use her for this one?
I love [name_f]Olympia[/name_f]! I think she’s perfect with [name_f]Aphrodite[/name_f]. Though I do see that it might lock you into a bit of a Greek theme.
Boadicea: While this is not my favorite, it’s quite pretty and has lots of cute nickname options.
[name_f]Cleopatra[/name_f]: [name_f]Love[/name_f] love love! Perfect with [name_f]Aphrodite[/name_f] and perfect nickname of [name_f]Cleo[/name_f]!
[name_f]Isolde[/name_f]: I absolutely adore this one too. Your pronunciation of it is the most beautiful [name_f]IMO[/name_f] and I just think it’s wonderful.
Nimue: [name_f]Love[/name_f] the namesake and love the sound.
[name_f]Guinevere[/name_f]: Stately, regal, and beautiful.
My top five (in no particular order) of your old faves: [name_f]Morgana[/name_f], [name_f]Olympia[/name_f], [name_f]Isolde[/name_f], [name_f]Cleopatra[/name_f], [name_f]Guinevere[/name_f]
Now for opinions on your new additions. I’m just going to be very straightforward with you:
[name_f]Angharad[/name_f]: I’m sorry but it sounds harsh to me. I also don’t like the idea of having two A first initials (as well as yours, correct? Is Husband an A as well?) However, I love the meaning (most love if I’m not mistake). Perhaps as a middle.
[name_f]Artemisia[/name_f]: Again with the A thing, as well as the [name_u]Artemis[/name_u]-[name_f]Aphrodite[/name_f] connection. I’d nix this one, though I think it’s a gorgeous name.
[name_f]Atalanta[/name_f]: I feel like it’ll be misread as [name_f]Atlanta[/name_f] a lot, and the A initial again - but if it doesn’t bother you, then don’t worry about it! Beyond that, I think it’s quite pretty. Middle maybe?
Belphoebe: This has been a favorite for quite a while, yes? While I think it’s very beautiful, I do think there’s an excellent chance of it being shortened to either [name_f]Belle[/name_f] or [name_f]Phoebe[/name_f], both relatively “common” names. Provided that possibility doesn’t bother you, I say go for it.
[name_f]Callisto[/name_f]: Gorgeous! That is all.
[name_f]Cassandra[/name_f]: I think this one is beautiful as well. Does the fact that it’s more popular bother you? Perhaps better suited to her normal middle?
Coventina: I just see coven and then I think of vampires. You’ll have to give me the pronunciation of this one, for I’m unfamiliar with it. But as I’m pronouncing it right now, I’d veto it.
Daronwy: Spelling looks awkward and masculine to me. However, I did a quick search and it looks to have a good namesake. You really know your stuff as far as mythology & literature are concerned, don’t you? I’m quite impressed!
Elbereth/Elentari: I think I prefer Elentari. [name_m]Both[/name_m], however, are very pretty names. I don’t know if I love how either looks in a sibset with [name_f]Aphrodite[/name_f] though. I think I might like both better as middles.
Galadriel: I know who the LOTR namesake is, but I still see [name_m]Gabriel[/name_m]. I don’t know why, I just do! I wish I loved it
Maybe a middle? It is VERY [name_m]Lord[/name_m] of the Rings.
Hespera: I do think it’s beautiful, but it will be just as nice as a middle for [name_f]Morgana[/name_f]. If your husband doesn’t love it and you can’t convince him to, I wouldn’t push it. Not worth the headache!
[name_f]Inanna[/name_f]: I’m indifferent to this one. [name_m]Don[/name_m]'t love it, don’t hate it.
[name_f]Isabella[/name_f]: AHHHHHH OMG [name_f]LOVE[/name_f]! [name_f]Love[/name_f] love love love love. I have always loved the name [name_f]Isabella[/name_f]. It’s been my number one name since looooong before Twilight and I’m trying so hard not to let the popularity bother me. I think [name_f]Aphrodite[/name_f] and [name_f]Isabella[/name_f] are adorable together. However, I’m worried about the popularity gap and whether they will be jealous of one another’s names. It does sound rather tame next to [name_f]Dita[/name_f].
Laudine: I like it but don’t love it. Maybe middle?
[name_f]Melusine[/name_f]: Ooooh, very pretty. I wouldn’t let the Starbucks logo bother you. Who knows that thing’s name anyways? Very slinky and slippery.
Nehalennia: Spelling looks awkward to me and pronunciation is not intuitive. I’d nix it.
Ostara: We’ve just been out west and all I can think of is the beautiful star-filled sky we saw every night out there. It brings up a gorgeous picture in my mind! Though for some reason, I’m having trouble picturing it on an actual kid and adult.
[name_f]Pandora[/name_f]: So gorgeous! If you can’t get it for a first, try to put it in the middle.
Pulzella: I don’t love the sound, though [name_f]Zella[/name_f] would be a cool nickname.
[name_f]Rhiannon[/name_f]: Feels tame next to [name_f]Aphrodite[/name_f] (this from the girl swooning over [name_f]Isabella[/name_f], LOL)
Silmarien: Sounds too close to [name_u]Marian[/name_u] in [name_f]Aphrodite[/name_f]'s name.
[name_f]Titania[/name_f]: Very pretty.
Trephina: I just don’t like the sound or the vibe I’m getting. Who are you referencing here?
Undomiel: [name_m]Don[/name_m]'t love the sound. Veto.
Valkyrie: I do think of airplanes. I know you’re honoring Norse mythology, but I also think of airplanes.
[name_f]Veronika[/name_f]: Feels too normal (even though I was swooning over [name_f]Isabella[/name_f]. Yes, I’m aware that I am a hypocrite).
So, to wrap it up, I would keep these names from your new list: [name_f]Atalanta[/name_f], Belphoebe, [name_f]Callisto[/name_f], [name_f]Cassandra[/name_f], [name_f]Isabella[/name_f], [name_f]Melusine[/name_f], [name_f]Pandora[/name_f], and [name_f]Titania[/name_f]. The rest I would use as middles or veto (I marked the ones I would get rid of).
I can’t pick an overall top five! I’ll come back later with some suggestions and hopefully an overall top as it’s late here and this is a huge post!!