Oooh, I like your style.
Heidi - quite like it. Don't love. Good for a middle name, it's not just a 'filler'.
Olive - only name on your list I really don't like. I feel like it's a less popular Olivia for a good reason - the ia is what makes Olivia a pretty name to my ears.
Raya - like it. Why don't you think it fits you?
Eira (ay-ra) - like it. Never heard it before. People would learn to pronounce it.
Piper - really like it. I do only know a dog with the name but I think it's so cute, cool and quirky for a girl and woman too.
Astrid - love it. One of my favourite girl names. Trending, I think, but I've only ever met one personally.
Willow - quite like it. I would worry that she wouldn't grow up to be willowy though and then might get teased. But that's probably my insecurity.
Ruby - like it. But yes, think it's more popular than your others. Though most of the ones I know are 10+ now.
Ember - like it. And have never met one.
Alba - really like it. Never met one.
Autumn - quite like it. Pretty popular but I only know a couple.
Margot - not keen but nothing really against it.
I'd choose Astrid from your list, closely followed by Piper and Alba.
Other ideas that are similar in my mind:
Aphra, Amaya, Amberley, Anika, Aria, Arwen, Aven, Bronte, Bethan, Briar, Cleo, Cora, Carys, Cerys, Celyn, Celest, Cherry, Dana, Danica, Delphi, Everly, Ebony, Effie Etta, Enya, Elowen, Fleur, Faye, Fabia, Greta, Giselle, Gloria, Halle, Hebe, Hazel, Isolde, Iona, Iris, Ivy, Ingrid, Inga, Irma, Inez, Juno, Juniper, Jacinta, Jonquil, Jemima, Kiki, Keziah, Keltie, Livia, Lyra, Liara, Luana, Mika, Mala, Merryn, Maeve, Misty, Miranda, Nova, Nyla, Nyah, Noelle, Odette, Ottilie, Pippa, Posy, Polly, Quinn, Rivkah, Remi, Romy, Rowan, Rowena, Rosina, Robyn, Robina, Romilly, Ramona, Rosa, Sadie, Saffron, Sylvia, Seren, Samaris, Summer, Sorrel, Tamara, Tamsin, Thea, Thalia, Taryn, Tansy, Verity, Vanessa, Winter, Willa, Xanthe, Ysanne, Zola, Zia, Zeryn