Oh wow exciting! A namers dream, twin girls! And you’re using two middles, and your hubby is a name lover too - this is so fun! 
As far as first names, I think all your pairings match except [name]Annelie[/name] and [name]Lucille[/name]. On one hand there’s the fact that [name]Lucille[/name] feels very vintage and [name]Annelie[/name] very modern ([name]Annelie[/name] was a huge love of ours for a while), but there’s also the fact that they have overlapping sounds, I find they run into each other a bit when I say them together.
[name]Eloise[/name] and [name]Violet[/name], [name]Beatrice[/name] and [name]Felicity[/name], and [name]Millicent[/name] and [name]Frances[/name] are gorgeous though.
Personally, my favourite pairings are:
[name]Eloise[/name] and [name]Felicity[/name] - both super elegant, sophisticated and feminine
[name]Millicent[/name] and [name]Lucille[/name] - [name]Millie[/name] and [name]Lucy[/name]? I like the repeating double l’s but they have distinct sounds
[name]Violet[/name] and [name]Frances[/name] - sweet, simple and vintage - [name]Lettie[/name] and [name]Franny[/name] are too cute!
[name]Beatrice[/name] and [name]Millicent[/name] - a little buttoned up and quirky, I like [name]Bea[/name] and [name]Millie[/name]
[name]Eloise[/name] and [name]Francesca[/name] - not sure if you’d consider [name]Francesca[/name] but I think it works better with [name]Eloise[/name] than [name]Frances[/name]
[name]Annelie[/name] and [name]Felicity[/name] - matchy endings, but the sounds are distinct so I think it’s ok
[name]Violet[/name] and [name]Beatrice[/name] - [name]Vi[/name] and [name]Bea[/name]?
[name]Anneliese[/name] and [name]Felicity[/name]
[name]Anneliese[/name] and [name]Millicent[/name] - [name]Annie[/name] and [name]Millie[/name]?
My top 3 would be: [name]Eloise[/name] and [name]Felicity[/name], [name]Violet[/name] and [name]Frances[/name], [name]Beatrice[/name] and [name]Millicent[/name] and one extra - [name]Francesca[/name] and [name]Eloise[/name] (if you’d consider [name]Francesca[/name]).
I love almost all of your middles, how about:
[name]Eloise[/name] [name]Matilda[/name] [name]Jane[/name] and [name]Felicity[/name] [name]Margaret[/name] [name]Claire[/name]
[name]Violet[/name] [name]Camilla[/name] [name]Wren[/name] and [name]Frances[/name] [name]Adela[/name] [name]Rose[/name]
[name]Beatrice[/name] [name]Annabelle[/name] [name]Mae[/name] and [name]Millicent[/name] [name]Adela[/name] [name]Blythe[/name] (reversed initials!)
[name]Eloise[/name] [name]Camilla[/name] [name]Faye[/name] and [name]Francesca[/name] [name]Juliet[/name] [name]Grace[/name]
[name]Hope[/name] that helps, I could go on and on with combos as your names are fab! 