Absolutely love Elara she’s beautiful 
From the names you’ve listed I think Calliope has the right sparkly feel. Elara & Calliope would be perfection.
You’ve had lots of lovely suggestions so please count any repeats as me being in agreement with the berries
Elara and…
Artemis ~ Arty
Selene ~ Leni
Persephone ~ Sephy
Seraphine ~ Sera
Aurelie ~ Goldie
Romilly ~ Millie
Anouk ~ Annie
Juno ~ Junie
Araceli ~ CeCe
Ottilie ~ Tillie
Ione ~ Io
Amalthea ~ Thea
Isabeau ~ Beau
Imogene ~ Immy
Fabienne ~ Fab
Pomeline ~ Pommy
Delphi ~ Fi
Noemi ~ Mimi
Saffron ~ Ronnie
Hope this helps