I normally dislike it when twins are named using the same initial, but some of these aren't bad.
I like these:
Hazel and
HugoAva and
AlexanderSophia and
Samuel
These are terrible:
Taylor and
TylerMadison and
MasonChristina and
Christian
Vivienne and
Val - I like
Vivienne, but
Val is a nickname. If it's short for
Valentine /
Valentino then it's a nice pair.