If it's just a nickname, her first name could be anything really, but if you want something close to
Blaise, how about
Blythe? There's also
Blazenka, a feminine Croatian form of
Blaise. Or perhaps Blasia inspired by
Blasius, the original Latin form of
Blaise?
For the boy:
VirgilVincentEdmundEdwardSebastianHeathcliff "
Heath"
Remington
Kenzington / Kensington
AlfredAlbertAlexander (no nickname)
Frederick (no nickname)
AlaricNigelJames - Not exactly snooty, but paired with the right last name, it could be. Something like
James Kenzington or
James Windsor would work.
WinstonCharlesSidneyLucian