Iris - the meaning is nice and I like the name
Willa - like it but maybe nicer as a diminutive for Willow
Esme - sorry, twilight ruined forever that name for me
Clara - sounds old to me. Like Clarissa - Clary.
Pearl - not a fan of one syllable names. They sound abrupt and unfinished to me.
Hazel - why not. No strong feelings on this one.
Margot - isn't that a diminutive of Margaret ? Either way, not a fan. Sounds old fashioned to me.
Violet - sorry but I don't like it. Sounds close to "violated" to me. Also sounds old, though I know it's quite popular atm so maybe that's just me.
Olive - nice but prefer Olivia
Grace - dislike. No reason. Just don't like the sound and again, one syllable names
Mabel - sounds old fashioned to me
Merryn - like it. Nice sound.
Lyra - like very much. Poetic, strong.
Phoebe - not a fan.
Connie - short for Constance. Not a standalone name imo.
You seem to like the greek classical names so I would suggest :
Helen
Lydia
Diane
Chloe
Daphne
Eirene
Juno
Phaedra
Rhea
Thalia