I would love to see Vivian, nn Vivi, but I think it is too cutesy to stand on its own. Olivia, nn Livi would also be better, but Olivia is so popular that I would avoid that one. My order of preference would be:
I voted for Vivi (and I see I'm way outvoted!) I did it because I know a woman named Viviane whose husband calls "Vivi" (pron vee-vee). it is such a cute nickname-- but I would definitely use it as a nn rather than a full, given name.
I would love to see Vivian, nn Vivi, but I think it is too cutesy to stand on its own. Olivia, nn Livi would also be better, but Olivia is so popular that I would avoid that one. My order of preference would be:
Vivian (nn Vivi)
Hope
Claire
Olivia (nn Livi)
I totally agree.