I don't really like theme names for siblings, like London and Ireland or Ava and Ana, but lately I'm liking middle name themes, mostly for twins, like:
Lauren Faith and Juliet Grace (Faith and Grace as middle names)
Lily Sara and Sofia Loraina (LS and SL)
and "cross theme" names where one fn is a theme with a mn and the other fn is a theme with the other mn, like:
Lily Cristina and Sofia Rose (Lily and Rose both being flowers, Cristina and Rose both being Spanish names)
Caoilainn Elisabeth (kay-lynn)and David Sean (Caoilainn and Sean are Irish, Elisabeth and David are biblical)
So what do you think of sibsets with themes like this? Sorry this is so long and I tried to make some sense!