I still really love [name_f]Evangeline[/name_f] as it is timeless. Others are [name_f]Margot[/name_f], [name_f]Genevieve[/name_f], [name_f]Freya[/name_f], [name_f]Cordelia[/name_f], [name_f]Amelie[/name_f], [name_f]Theodora[/name_f], [name_f]Isadora[/name_f], [name_f]Isla[/name_f], [name_f]Phoebe[/name_f] & [name_f]Penelope[/name_f].
Good [name_m]Luck[/name_m].
Thanks again! So we both like [name_f]Freya[/name_f] and [name_f]Delilah[/name_f] (though I don’t love that specific Biblical association). We also both adore [name_f]Greta[/name_f], but we used it for one of our cats a couple years ago 
A few more …
[name_f]Greta[/name_f] => [name_f]Ingrid[/name_f], [name_f]Astrid[/name_f], [name_f]Etta[/name_f], [name_f]Greer[/name_f], [name_f]Giselle[/name_f]
[name_f]Freya[/name_f] => [name_f]Aurelia[/name_f], [name_f]Thea[/name_f], [name_f]Annika[/name_f], [name_f]Anya[/name_f], [name_f]Fiona[/name_f], [name_f]Maeve[/name_f]
[name_f]Delilah[/name_f] => [name_f]Talullah[/name_f], [name_f]Lorelei[/name_f], [name_f]Tabitha[/name_f], [name_f]Juliana[/name_f]
[name_f]Gwendolyn[/name_f] => [name_f]Genevieve[/name_f], [name_f]Jocelyn[/name_f], [name_f]Adeline[/name_f], [name_f]Emmeline[/name_f]
[name_f]Britta[/name_f]
[name_f]Brigitte[/name_f]
[name_f]Cassandra[/name_f]
[name_f]Nerissa[/name_f]
[name_f]Claudia[/name_f]
Both of your lists are lovely, and I thin finding middle ground won’t be too difficult because there are recurring themes throughout your lists. First two names that popped to mind were [name_f]Genevieve[/name_f] and [name_f]Amelia[/name_f]. Both feel current and modern, but have a long history of usage. Both are lovely and feminine, but also strong and spunky, much like your [name_u]Eloise[/name_u].
The main commonality that jumped out at me from both of your lists was a strong but subtle nature theme. Would names like [name_f]Ivy[/name_f], [name_f]Iris[/name_f], or [name_f]Jade[/name_f] appeal to you? I especially like [name_f]Ivy[/name_f]. [name_f]Ivy[/name_f] and [name_u]Eloise[/name_u] strike me as a gorgeous sibling pair.
Other excellent in-between choices include:
[name_f]Annika[/name_f]/[name_f]Anneliese[/name_f]/[name_f]Annelise[/name_f]: An- names are very much in right now, but all of these names have a long history of use.
[name_f]Adelaide[/name_f]/[name_f]Adele[/name_f]: These names have seen a recent resurgence, but not enough to make them extremely popular. I could see them on an 8-year-old or an 80-year-old, and find them universally gorgeous.
[name_f]Edith[/name_f]: If you don’t mind your daughters sharing initials, I think this one is worth close consideration. It has the timeless feel of your names, but is making a comeback like many of your husband’s choices.
[name_f]Caroline[/name_f]/[name_f]Catherine[/name_f]: Both true modern classics, and well-matched to [name_u]Eloise[/name_u].
[name_f]Phoebe[/name_f]: I love this name for you. It is current and recognizable, without being overused, and has been used from Shakespearean times to today’s television shows. Plus, [name_f]Phoebe[/name_f] and [name_u]Eloise[/name_u] sound great together!
I think my personal top three picks from this list, in no particular order, would be [name_f]Phoebe[/name_f], [name_f]Ivy[/name_f], and [name_f]Genevieve[/name_f]. Best of luck going forward! 
Change your cats name to [name_f]Greer[/name_f] and name your daughter [name_f]Greta[/name_f] 
[name_f]Gwendolyn[/name_f] => [name_f]Rhiannon[/name_f]
[name_f]Greta[/name_f] => [name_f]Petra[/name_f]
Could his flickering interest in [name_f]Laurel[/name_f] lead him to [name_f]Marigold[/name_f]?
My first thought was [name_f]Cecily[/name_f]- classic, a little whimsical like [name_u]Eloise[/name_u], and also feels at home among the kind of names your husband likes. I also love the rhythmic sound of [name_u]Eloise[/name_u] and [name_f]Cecily[/name_f]. A few other ideas:
[name_f]Cecilia[/name_f]
[name_f]Zelda[/name_f]
[name_f]Anabel[/name_f]
[name_f]Lucy[/name_f]
Good luck!
I like [name_u]Eloise[/name_u] and [name_f]Phoebe[/name_f].
Or
[name_f]Zoe[/name_f]
[name_f]Sadie[/name_f]
[name_f]Stella[/name_f]
[name_f]Iliana[/name_f] is a great choice in my opinion. It’s uncommon and beautiful, but it also has a bit of a modern edge to it. The feminine name [name_f]Camille[/name_f] is also a great option. [name_f]Ashlynn[/name_f] might be something you’d want to use as well: it’s very pretty but has a unique twist on the end.