Avalon (nn Ava, Avvy) - I want to like this but I just can't for some reason. I like the sound but it is too much of a place name for me. I would like it on someone else's child though, just not my own.
Aurora (nn Aurie) - I also want to like this because it sounds pretty and the nickname Rory would be so adorable, but I'm just not too keen.
Collette (nn Lettie) - This is okay, it's a little harsh sounding for me.
Daisy - Very, very cute, but I am with some of the other posters in that I worry it wouldn't age well. This is unfortunate because I really love this name too.
Isabella (nn Bella) - I really, really love Isabella. It is so lovely sounding and rolls off the tongue. But I really can't get past its popularity unfortunately, and this upsets me because it is my grandmother's name and I would have loved to have used it. I prefer the Scottish variant Isobel now, because it is much less common. I'd also use Izzy as a nickname, as it's less popular that Bella.
Lily - My favourite girl's name EVER. But again, the popularity turns me off. It's my other grandmother's name and I will probably use Lillian or Lilliana instead (nn Lily).
Josephine (nn Josie) - Love!
Madeleine (nn Maddy) - I love this, but again, so popular! I hate that all the gorgeous names are in such common usage, I would rather people stick with tryynddee spellings and let me (and others on here) keep these names. I don't like the nn Maddy though. Maybe Lainey?
Noella (nn Ellie) - Not a huge fan.
Violette (nn Lettie) - Not a fan of Violet/Violette very much.
Favourites (regardless of popularity) - Lily, Isabella, Josephine, Madeleine.
I do really like your list, BUT I am not a fan of nicknames unless it makes sense as in josie.
Avalon (nn Ava, Avvy) love the name dont like nn
Aurora (nn Aurie) this name is the least distinct on your list although still nice, nn not good
Collette (nn Lettie) collette nice lettie gross
Daisy: maybe as a nn for Margaruite? but as a sand alone its too cutsey
Isabella (nn Bella) NO NO NO way too popular
Lily cute although popular
Josephine (nn Josie) like
Madeleine (nn Maddy) also way too pop
Noella (nn Ellie) just ok
Violette (nn Lettie) I like the double E T spelling so cute like nn Vi or VIVI but not lettie