I love your style.
I voted for Beatrix Odette, Blythe Susannah, Louisa Betty, and Hazel Thomasine. They're all striking choices with the same retro throwback feel as your other children's names.
With Ramona, Frances, Calvin, Esther, and Margot, I think my favorites are Louisa and Hazel. They feel so natural as sibling number six.
The only fn I don't like with Ramona, Frances, Calvin, Esther and Margot is Blythe. It has more of a contemporary feel than the vintage names of your children so I would use it for a middle name. I also think Ramona/Margot/Nora are a bit too similar. I voted for Sylvie Maude and Hazel Thomasine on your poll. I love some of the other names but not with the middle name choices.
These names would be lovely with Blythe in the middle spot...
I adore Sylvie! Don't really care for either of your middle name choices. I feel like it needs something a bit more girly and less old lady because Sylvie is already an older type name. How about:
Kind of typical, but I think they go better.
Thank you all for the responses. It's interesting to see that several people suggested Louisa Blythe and Susannah Blythe - both lovely combinations.
sarahmezz - Beatrix Pearl was one of the names on our list that missed out on being included in the poll, which allows only ten choices. We ultimately went with the other options because we think the alliterative Beatrix Blythe and the offbeat Odette are a bit more unexpected than Pearl.