What a funny group of responses! Since Charlotte and William are both family names for me, they don't register. Plus, my Charlotte is 14 so I blame Kate Middleton for this overlap.
I’d pick Gwendolyn. You could always do Caitlin / Catherine and call her Kate for a bit less of a Royal overlap. Bronwyn may be a tough name in the schoolyard.
Re: Charlotte, William and.....
with your siblings I’d say Robert and Gwendolyn
I would pick Bronwyn or Gwendolyn for a girl and Eli or Christopher for a boy. Some other ideas based off of your list:
Anna
Bridget
Cynthia
Eleanor
Eve
Evelyn
Hannah
Isabella
Jillian
Morgana
Paige
Sophia
Susanna
Adam
Archibald
Ian
Jeremiah
John
Lee
Noah
Reginald
Richard
Samuel
Simon
Thomas
Zachary
MMC 8/5/15 at 8 weeks
DS born 9/13/16
BFP 1/13/18 - EDD 9/20/18 - It's a boy!
Bronwyn may be a tough name in the schoolyard.
Elisabeth
Gwendolyn
Robert
Andrew