Baby Girl or Boy, Sibling to Madeline Claire

Tara writes:

We are looking to name child #2, sex unknown, due September 30th. We have one daughter named Madeline Claire. For girl names we tend to like more of the timeless/elegant/classic names. If it’s a girl I really want our first and second daughters names to go together. For boys we tend to go more for an all boy kind of name. I am not as concerned with the styles of boy and girl matching each other, but I do want the names to sound good together. As for popularity; I don’t really want a top 10 where the child will have 3 others having the same name in their classroom. We live in a smaller town where trends arrive later so a name that is projected to rise is not as big of a concern for me.
For girls:
--Kate: I love this name and wanted to use it for our first daughter. My husband thinks that it’s too bland to stand up next to Madeline
--Ella: My husband loves this name; it would be his first pick. I like the name, but I fear that it’s too popular.
--Gabby: We both like this name. We would probably name her a longer version and then call her the nickname. The concern: we don’t call Madeline “Maddy” as a nickname but I do hear it from some friends and family so I worry about having a Maddy and a Gabby.
--Lucy: We both like but also worry about it sounding good with Madeline and getting too popular.
--Grace: Same worries as with Lucy. (Have considered using as a middle name)
--Arden: I really like this name, but not sure if it really goes with the style of the other names on our list. I want the name to definitely be a girl name and think this may be one of the in between names that could be used for both sexes

For boys:
We don’t really have top names for a boy. If our first child had been a boy the top contenders where: Miles, Griffin, Cole, Heath, and Cooper. But none of those names would work now for various reasons. Other names on the list are:
Reid, Jack, Grant, Blake, Brent, Mack, Will
I also love the idea of using a surname but haven’t found one that is not being used by friends/family that I like.

Any suggestions would be appreciated. Thank you.