Do you mean to say
Nura and
Nerina as twins, and
Arianna and
Aurora, and
Maya and
Michelle?
I don't think that twins need to deliberately be given the same initial. I'd choose two names I liked that went well together just as would with any other two daughters born apart. Maybe
Agatha and
Beatrice, or
Agatha and
Cordelia, or
Beatrice and
Cordelia. Ugh, maybe I'd be better off having triplets. ;)