Please shred our shortlist!

Aileen -like
Ailsa- like
Audrey -like
Bethan -like
Blair -boys name
Bryn -not so keen
Callisto - dislike
Daphne - quite like, a bit different
Darcy - dislike
Eilish - ok
Fearne - dislike
Grier - no
Hazel - ok
Juliet -really like
Lena - ok
Mara - ok
Marion - ok
Natasha -quite nice
Roisin - like
Rowan -like
Vhairi - ok
Winter - no, just no

Boys:

Augustus - dislike
Blair - like
Conrad - really like this
Corran -Meh
Ellis -like
Gil - ok but would have as short for something.
Hamish -like
Harris -like
Seamus -ok

Ailsa or Audrey and Conrad probably my favourites

I don't like Bryn, Blair witch or Grier or Winter.

Not sure about Augustus (Gloop). If you like Gus why not Angus?

All the others fine.

I feel a bit mean but you did ask for 'shredding'

Aileen - like it
Ailsa - like it
Audrey - like it
Bethan - nope
Blair - like it but only for a boy
Bryn - Nope
Callista - Hmm - maybe
Daphne - Nope
Darcy - nope
Eilish - like it
Fearne - nope
Grier - like it
Hazel - its okay
Juliet - like it
Lena - it's okay
Mara - Hmm - maybe
Marion - Nope
Natasha - Nope
Roisin - like it
Rowan - like it but only for a boy
Vhairi - like it
Winter - nope

Boys:

Augustus - nope
Blair - like it
Conrad - nope
Corran - like it
Ellis - nope
Gil - like it
Hamish - like it
Harris - like it
Seamus - Hmm Maybe

Fallon and Nyree would go well on your girls list. Brodie, Calvin and Keir would go well on your boys list as well as adding Rowan down from the girls list.

I like these:

Bethan
Daphne
Darcy
Juliet
Lena
Marion
Natasha
Winter

Ellis
Hamish
Harris
Seamus

Bryn is a male name, surely? Or am I imagining a man-mountain of a Welsh baritone with a voice like God?

And isn't the Scottish version of Mary/Maire Mhairi rather than Vhairi (though pronounced Vhairi)?

Of your list I like Mara and Roisin, Augustus, Gil and Seamus. Winter, Blair and Grier (Greer?) are gruesome.

Conrad or Juliet

Callista, hamish. Not fond of any of the others.

Love surnamey names for girls that should say , not hate.

Love Grier for a girl. Hate surnamy names for girls, yet despise them for boy. Natasha is gorgeous, too. The other names aside from Rosion which is also very pretty. Winter is great too and Winnie is a brilliant nn but as I am free you know it would only suit a child born in Winter.
Out of the boys I only like Conrad but I do like Gus as a nn for Augustus. I am really particular about boys names.

Natasha for a girl - great name (unlike Grier - is that a joke?)

Out of your boy names I would pick Conrad, I think.

Girls:

Aileen Like
Ailsa OK
Audrey Nice
Bethan Nice
Blair In theory I like this, but ... Tony. No.
Bryn Nice
Callista Nice, and I like Cally
Daphne Like this
Darcy Meh
Eilish Really like
Fearne Really like Fern, dislike Fearne
Grier Like
Hazel Love (high on my DH's shortlist, but I really don't think we can use it with our surname)
Juliet Nice
Lena Like
Mara Like
Marion Like
Natasha Meh
Roisin Like
Rowan Like
Vhairi Very nice
Winter Like - assuming it's a winter bub we're talking about?

Hmm OP we have some shortlist overlap on the girls!

Boys:

Augustus Like
Blair As above, no
Conrad Like
Corran Particularly like
Ellis Very nice
Gil Like
Hamish Like
Harris Like
Seamus Like

None of the boys are on my shortlist, but OP I think we have similar taste, so I'm not able to narrow it down very much!