If her birth parents are known, their last name could be used as hers. Otherwise, the name can be assigned at the orphanage/foster home/hospital they are left at. For example, my friend started out with the surname 'Smith', which was assigned by a nurse and approved after he was abandoned at a hospital and his parents couldn't be traced.
When he was adopted it changed to his adopted family's surname. When he finally traced his mother, he decided to take on her surname instead. Did her parents die after her birth, so their surname is known?
Or is she just abandoned, with no known family at all? If she was abandoned, or her parents are unknown, try something that's very common or 'plain', such as Smith, Brown or Cook.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.