I agree that [name_f]Neve[/name_f] should be [name_f]Niamh[/name_f], especially if you’re using it as an honour name in this way.
From your list [name_f]Niamh[/name_f] or [name_f]Imogen[/name_f] would be my favourites. What about:
[name_f]Bethan[/name_f]
[name_f]Florence[/name_f]
[name_f]Esme[/name_f]
[name_f]Thea[/name_f]
[name_f]Matilda[/name_f]
[name_f]Isla[/name_f]
[name_f]Harriet[/name_f]
[name_f]Clara[/name_f]
[name_f]Anwen[/name_f]
[name_f]Gwen[/name_f]
[name_f]Phoebe[/name_f]
[name_f]Alice[/name_f]
[name_f]Emilia[/name_f]
[name_u]Seren[/name_u]
[name_f]Iris[/name_f]
[name_f]Aoife[/name_f]
[name_f]Philippa[/name_f]
[name_f]Agnes[/name_f]
[name_f]Caoimhe[/name_f]