My favourites that go (slightly) with those names
Lorelei, Adelaide, Austen, Evelin (ev-ey-lin), Frankie, Tisbe (tiz-bee), Teirney.
Both Rosalie and Astrid are on my lists. My friend knows an Astrid and I think she was fine. I think it's a beautiful name and i didn't instantly think of asteroids or anything else. Bullying these days isn't teasing about names anyway, it's much more sinister :)
I really like Priya for a girl (pree-uh). Ends in an "a" but doesn't have the same sound as the boys names.
Other possibilities I think may be your style...
A biblical name like....
Lydia. (I know the ending on this one is the same, though).
Carys, karis, Charis
Delilah (love this one!) "Lilah"
Something classic but uncommon enough....
Rosie (or Rosalie like you said and Rosie for short!)
If you love Astrid, you should go for it! Some other suggestions - Isabeau, Clemency, Gwendolyn, Kirrily and Adeline. Good luck in finding the perfect name for your little princess.
When I saw your son's names it made me think that it was a biblical theme, and my mind went straight to Naomi.
With Ezra and Elijah, I like Biblical names.
Miriam, Naomi, Phoebe, Salome, Shiloh
If you wanted another E name, Eden would be a nice choice.
Ezra, Elijah, and Eden would make a great sibset.
I love Astrid! It's fantastic. I think the 'd' ending makes it stand out from the pack, as far as girls' names go.
Ezra, Elijah, and Astrid...I think that sounds great! I think sharing an A with you would make her feel special, especially since her brothers share the E.
Aww, I love Astrid! Maybe I'm a weirdo, but I think Asteroid would be a totally badass nickname haha. Anyhow, not 100% sure what you're looking for, but here is a random assortment from my list that I imagine a fan of Astrid and Rosalie might like:
Best of luck!