Honest Opinions- DD’s name

The majority of your list are quite unusual/ quirky so on that basis you are perhaps better avoiding Isla, Lola & Olivia because there are LOTS of young children around already with those 3 names

Of those that are left I like Polly, India & Coco best

Indigo (NN- Indie) - quite like this. Much prefer it to India
Blair - awful. Really masculine and horrible associations (Tony. Witch Project)
Willa - nice
Coco - awful as a given name. Cute as a nickname. I know a Constance known as Coco (she's in her 50s)
Silver - we discussed this recently. Not keen. Prefer Silva spelling. Much prefer Sylvie
India - don't like. Seems tacky.
Lola - it's ok. I'm not sure my generation is ever going to get past the stripper connotations
Isla - lovely, classic but fresh. But very popular
Olivia - boring
Olive - nice
Polly - gorgeous. I hate Molly and Holly (so dull) but Polly is lovely

For me it would be Polly then Olive, Willa or Isla followed by Indigo

Indigo (NN- Indie) - it would be cute on a toddler and small child, less so on a teenager. It's really not a name I would want as an adult though. 70 year old Indigo? Basically it's a very youthful name

Blair - Tony
Will - I like it
Coco - sounds like a pet name
Silver - I like it as a nn
India - Meh, unless you have some meaningful connection to the country
Lola - not a fan
Isla - they are everywhere
Olivia - ditto though prefer it to Isla
Olive - love it
Polly - like it

Indigo (NN- Indie) - I think this is more often used for a boy. I like Indie though. What about India. Indigo sounds like an internet provider or something.
Blair -I do like this, but I'd put an e on the end, Blaire.
Willa - not sure, prefer Willow but Willow is like Isla and Lola, was SO trendy that now it's a bit 'done'.
Coco - ok as a nn
Silver - again, use this as a nn for Sylvia - otherwise, hi ho Silver will drive her crazy.

India - like it don't love it.
Lola - ok, bit of a stripper name. Prefer Lyra
Isla - Ok, pretty but was nom du jour over five years ago now.
Olivia - ok. Prefer Livia
Olive - Ok. not sure I like that it's less frilly than Olivia but I just think of a stuffed Olive.
Polly - like it. Like Paloma and Penelope too and maybe Polly could be a nn for either of those.

Isla, Olivia - very commonly used, nice names, but now a bit boring because of this.
Blair - no opinion. Very surnamey
Willa - no opinion
Coco - seems too nicknamey to be a given name
Lola - as Isla and Olivia, with added showgirl connections
Olive - ok
Polly - LOVE IT!!!!

Willa would become Willie in seconds at school.

Indigo (NN- Indie) - hm, at a push
Blair - no, downmarket
Willa - yes, it’s got class, but people will think Willow.
Coco- I quite like this. I do know one. But I’d never use it as a proper name.
Silver- Quite like but I’d assume you had Romani links.
India- no way. Borderline offensive.
Lola- bland, downmarket. Good if short for something else, like Louisa.
Isla- I do quite like it but it’s popular.
Olivia- as above.
Olive - seems a bit dreary to me.
Polly-yes, growing on me. I know a ten year old one.

Indigo (NN- Indie) - not a fan
Blair- witch, Tony
Willa- Nope
Coco- the clown, Chanel, pops
Silver- usually a boy's name in my experience
India- OK. Katie Hopkin's kid's name
Lola- more of a dog's name to my mind
Isla- OK, a bit popular for my tastes
Olivia- see above
Olive- Oil
Polly- wanna cracker? Also Aunt Polly from Mr Tumble and Miss Polly who had a dolly who was sick, sick, sick

Don't like any but the best to my mind are India and Isla (providing you don't have an inappropriate surname, such as White or Mann).

Indigo (NN- Indie) Don’t mind indie but dislike indigo
Blair - love
Willa- too much teasing potential
Coc - ok but prefer as a nickname
Silver - just no, Sylvie?
India - better than indigo
Lola - Charlie and Lola
Isla - lovely but v popular
Olivia - lovely but very popular
Olive- like
Polly - dislike

Blair is horrible (Tony Blair / Blair With/ Bla Bla Bla)

Sylvie is nicer than Silver IMO

I like the rest.

My favourites from your list are:

Indigo
Coco
India
Isla
Olivia
Polly

I really don’t like Olive or Blair.