It is definitely a name. I'm not sure how I feel about it - quite like it I think. Also not sure how to spell it.
I really like Neive but I would spell it Niamh. I've seen Neve and Nieve but never Neive actually.
I don't know what kind of alternatives you're looking for but maybe:
Alternative 'unusual ie names':
Hannalie, Amberley, Coralie, Natalie, Persephone, Siddalee (sp?), Cassidy, Verity
Alternative 'Celtic' names:
Aoife, Aisling, Maeve, Caoimhe, Ffion, Fionnhuala, Morvern, Eilidh, Catriona, Fiona, Roisin
Alternative 'O' names:
Orla, Odette, Odille, Ocean, Olga, Olive, Olivia, Ophelia, Octavia, Oriana, Opal
Alternative 'N' names:
Nina, Nadia, Nadine, Nia, Nyah, Natasha, Naomi, Natalia, Nora, Nancy, Noelle, Noa, Neriah, Nesta