Factual error: When Topanga and Ricky are looking at the Starry Night painting, Topanga reads from her pamphlet and says it mentions Vincent Van Gogh became religious around the time he painted it. Van Gogh grew up in a religious household, with his father being a minister of the Dutch Reformed Church, and Vincent himself actually had a desire to become a pastor. On the contrary, however, when he painted Starry Night, although he still believed in an afterlife, he was actually disillusioned with religion.
Factual error: The Starry Night painting that characters look at in the Van Gogh exhibit is mentioned as being the original painting itself. However, if you compare the painting presented in this episode with the real-life painting that is displayed in the Museum of Modern Art, you can see that it is an imitation, as the colors are brighter and the little details in the painting are not as prominent.
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.