I think it depends on what middle name you are considering and how the whole name sounds together. Most importantly, how the first and last name sound together.
My instinct is to say use [name_f]Eleanora[/name_f], because it is less used and to me more interesting. Then you have the option of the shorter name [name_f]Nora[/name_f] as a nickname. [name_m]Other[/name_m] nickname possibilities are [name_f]Elle[/name_f], [name_f]Ellie[/name_f], [name_f]Annora[/name_f] and [name_m]Lea[/name_m]. Both girls will then have three syllable names. [name_m]Liam[/name_m], [name_f]Selena[/name_f] and [name_f]Eleanora[/name_f] make a great sibling set. That being said, [name_m]Liam[/name_m], [name_f]Serena[/name_f] and [name_f]Nora[/name_f] work well together, as well.