Paloma Olive is a gorgeous name! I really like Iris and Plum from your list. I have Plum as a nickname for Paloma on mine 
Some ideas to go with Paloma Olive:
Una
Lavender
Jemima
Sienna
Talulah
Tabitha
Willow
Ida
Vera
Blythe
Colette
Aubrie
Eden