[name_m]Hi[/name_m] there.
[name_f]Diana[/name_f] & [name_f]Rosalind[/name_f] are really lovely. They totally have a similar vibe.
Here are my thoughts on your lists:
Girls-
Leonore-I don’t know. I like that it’s different & feminine w/out being frilly. Which is good w/your daughters’ names. I just think that it sounds a little too dark & kind of awkward to say. Because it’s almost like [name_f]Eleanor[/name_f], but it’s not. I love [name_f]Eleanor[/name_f], but it’s very popular which you may not like. I also love [name_f]Leora[/name_f], but that ends in an ‘a’
Calliope-This is so fun. I love the fairy like spunk of it. It seems a bit of a different style from [name_f]Diana[/name_f] & [name_f]Rosalind[/name_f] (even though it’s Greek like Diana), but it doesn’t not fit.
Beatrice-This is a great name. It’s smart & sweet & thoughtful & vintage. It’s easy & well known, but not too popular. A great fit w/your crew.
Helen-I don’t mind [name_f]Helen[/name_f]. It’s old fashioned & simple & not popular. And I love the nn [name_f]Nellie[/name_f]! But I just never could get into it because of the ‘Hel’ sound.
Tallis-Not a fan of this one. It doesn’t sound very pretty to me, but it’s not horrible. I really love [name_f]Talia[/name_f] for you, but it ends in an ‘a’.
Margaret-A nice classic. A name that I like in theory more than the actual sound, but it’s still a good choice. Especially w/all of the cute nns. [name_f]My[/name_f] favorites are [name_f]Maisy[/name_f] & [name_f]Gerty[/name_f], but I also like [name_f]Molly[/name_f], [name_f]Peggy[/name_f] & [name_f]Maggie[/name_f].
Bryony-I want to like this. It’s floral & it’s unique & a really cool fit w/Diana & [name_f]Rosalind[/name_f]. I just don’t like the sound, because it reminds me of Bryan-ee.
(I love [name_u]Hillary[/name_u], [name_f]Cosima[/name_f], and [name_f]Salome[/name_f], but DH not keen and probably rightly so)-Salome
Too bad your dh doesn’t like it.
A few ideas that you may like-
[name_f]Anais[/name_f]
[name_f]Abigail[/name_f]
[name_f]Bridget[/name_f]
[name_f]Bernadette[/name_f]
[name_f]Clementine[/name_f]
[name_f]Esther[/name_f]
[name_f]Frances[/name_f]
[name_u]Marian[/name_u]
[name_f]Marisol[/name_f]
Marigold…it ends in a ‘d’, but not an ‘nd’. 
[name_f]Margot[/name_f]
[name_f]Olive[/name_f]
[name_f]Pearl[/name_f]
[name_f]Penelope[/name_f]
[name_u]Vivian[/name_u]
[name_f]Violet[/name_f]
Boys-
[name_u]Lawrence[/name_u] / Laurence-I very strongly prefer [name_u]Laurence[/name_u]. Not sure why. I think it’s fine. It doesn’t excite me, but it’s not a bad name.
Lowry-It’s not bad; kind of hard to say. [name_u]Lawrence[/name_u] (probably this spelling, actually) nn [name_u]Lowry[/name_u] might be fun.
Miles-It’s not bad, but by gosh, I meet so many little Miles’. It feels really over done to me. I prefer [name_u]Milo[/name_u] too.
Percy-Cute, but just a bit too cute. I think I like it for a cat. 
Barnaby-So charming & adorable. I wouldn’t be brave enough to use it myself, but it’s a great name. Fun & posh & well known but not done. Nice w/your girls’ names too.
A few boy ideas-
[name_m]Albert[/name_m]
[name_u]Bennett[/name_u]
[name_m]Bernard[/name_m]
[name_m]Caspar[/name_m]
[name_m]Jerome[/name_m]
[name_m]Malcolm[/name_m]
[name_m]Niles[/name_m]
[name_m]Philip[/name_m]
[name_m]Peter[/name_m]
[name_m]Simon[/name_m]
[name_m]Vincent[/name_m]
[name_f]Hope[/name_f] this helps. 