I'm not quite sure I can match your style, but I'll see what I've got.
Amarilla Florence (nn
Rilla) - I think this combo is nice enough, but maybe
Amarilla June would be nice as well.
Camellia Susan (nn
Millie) - Oh
Millie is sweet! I think this combo works.
Constance Isolde (nn
Connie) - I love
Isolde, but the s sounds are a bit close for me in this combo.
Constance Juliet?
Felicity Jane (nn
Flick) - This is lovely, I wouldn't change it.
Lavender Frances - I would switch out
Frances for
Alys.
Meredith Paget (nn
Merry) - I like this one as is.
Ravenna Acacia - I took out
Isolde above but maybe it would work here?
Ravenna Isolde?
Octavia Maris - This one flows well for me, I see no problems!
June Alys -
June Acacia?
June Amarilla?
I like
Cora a lot but I'm usually drawn to longer names, so I might prefer it as a middle name. That said, I am finding I like
Cora with a longer middle name that also ends in a, though that often bothers me.
Cora Mathilda,
Cora Francesca?