I have to ask about the pronunciation first... I instinctively say "ah-de-leh" but I have no idea if that's right.
As far as the names themselves as middle names, I really adore:
Aurelia,
Beata,
Cora,
Emilia,
Eugenie,
Giorgia,
Margot,
Mathilde,
Maud &
Maude,
Nora,
Opal,
Petra,
Rowena,
Virginia &
Virginie.
Lovely options!