I think it's neat that Grace and Miles both have 5 letters (my kids' names both have 8 letters), it's a subtle sibling connection. So my suggestions have 5 letters:
Ellen, Elise, Holly, Faith, Sarah, Korah, Fiona, Clare, Loran, Laura, Amber, Julia, Leila, Gemma, Jenna, Annie, Erica, and my fave with the others- *Betsy*
my faves with mn- Holly Rebecca, Faith Marie, Laura Kathryn, Julia Corinne, Leila Meredith
Gemma Rachel, Loran Tatiana, Ellen Callista, Korah Genevieve, Erica Juliet, Clare Christina
If you don't like the five-letter idea, others I like with your children are- Leah, Sage, Eleanor, Tatiana, Natalie, Beatrice, Bridget, Dana, Thea, Georgia, Isabel, Ava, Rosemary, Vivian, Jillian, Violet
Let us know what you decide and best wishes! Ginger
Devin (mom to Josephine Rosamel Anne)
Claire
Jewel
Rose
Kate
Katelyn
Lily
Brooke
Belle
Ellie
Laurel
Greta
Jane
Jade
Abby
Blair
Dora
Emma
Farah
Hope
Iris
Lana
Lainie
Maggie
Misty
Natalie
Noelle
Polly
Molly
Raina
Shayla
Tara
Wendy
Zara
HTH,
Ali
Ellen, Elise, Holly, Faith, Sarah, Korah, Fiona, Clare, Loran, Laura, Amber, Julia, Leila, Gemma, Jenna, Annie, Erica, and my fave with the others- *Betsy*
my faves with mn- Holly Rebecca, Faith Marie, Laura Kathryn, Julia Corinne, Leila Meredith
Gemma Rachel, Loran Tatiana, Ellen Callista, Korah Genevieve, Erica Juliet, Clare Christina
Betsy Marianne/Mariana, Betsy Kathleen, Betsy Natalia, Betsy Patrice, Betsy Millicent
If you don't like the five-letter idea, others I like with your children are- Leah, Sage, Eleanor, Tatiana, Natalie, Beatrice, Bridget, Dana, Thea, Georgia, Isabel, Ava, Rosemary, Vivian, Jillian, Violet
Let us know what you decide and best wishes! Ginger