Some thoughts:
Alessia (SS but not too close - eg Alessandra is too close to Cassandra for me)
Andromeda (I love this with your set!)
Anastasia
Antigone (can use Tigga or Tiggy as nn)
Valentina
Seraphina
Theodora
Isadora
Lydia
Sabina
Sabrina
Serena
Thalassa (again, not too similar)
Thessaly
Philippa
Luciana
Delphina
Rafaella
Sabella
Olympia
Octavia
Ophelia
And while Lee alone works wonderfully, you could experiment to see if Leanne, Leah or Leonie suits the rhythm and flow best to your last name. Eg I prefer Seraphina Leanne to Seraphina Lee with two syllable G last name.
I would go a non-C/ non-K starting letter to tie in Odessa (and Andreas). If it’s your last child, you may wish to use an O name (but at least a non C/K). One of the last three O names would be so beautiful especially Olympia or Octavia.