That sounds good to me. I'm sensing a theme in this family: first names that have awesome nicknames and middle names that aren't so easily shortened.
FNs: Agatha "Aggie", Evelina "Eve or Evie", Juliet "Julie or Jules", Katrina "Kat", Matilda "Tilly", Rosalind "Rosa or Rosie", Tamsin "Tammy",
MNs: Lydia, Violet, Scarlet(t), Carys, Athena, Daphne, Felicity, Naomi, Rowena, Silvia / Sylvia,