Alejandra was a historian and a tinkerer. She was a sex slave for 4 of her 22 years. After her master got married, she was sold to Hannibal Hamlin, who promptly freed her and ran away himself. She is quiet and smart, and has the best understanding of science and machinery of anyone in the Temple of the Union.
If the Lone Wanderer asks her what she does, she also admits she wants to build a shrine to Abraham Lincoln. It is unknown if this has anything to do with the strange shrine that already exists to him inside the basement of the Arlington House, but it is very improbable, as they aren't really linked.