I like all those names. Prefer the Zara and Amber pairing to the Rose and Ivy pairing but my favourites are Zara and Ivy.
Like your combos Zara Rose and Amber Ivy.
In a similar vein:
Astrid, Aria, Alexis, Bronte, Bryony, Carys, Cleo, Cora, Delphi, Dulcie, Devon, Erin, Effie, Eden, Erica, Faith, Fallon, Gabriella, Hanna, Iris, Iona, Josie, Jessamy, Kiki, Lyra, Lara, Lana, Livia, Mika, Mala, Miranda, Nyah, Nia, Noelle, Piper, Paloma, Quinn, Robina, Rosina, Rowena, Romy, Ramona, Robyn, Saffron, Sadie, Sorrel, Tansy, Taryn, Tegan, Verity, Vanessa, Wren, Xanthe, Zia, Zeryn