Well, it's possible that 'Black Butterflies' has elements of truth in it, but it could also be a completely fictional creation. The determination of whether it's a true story often involves research and understanding the context in which it was written.
It is indeed a true story. The author drew inspiration from historical facts and accounts related to the Mirabal sisters and their fight against the dictatorship.
Not necessarily. The butterflies in Peacemaker might have been inspired by the comics but could have some creative alterations or additions made for the show.