For Love and Apartments - S7-E2
Character mistake: When Shawn is scolding Topanga for getting angry with Cory for travelling to Pittsburgh to try to get her parents back together, he mentions that he travelled a hundred miles to do so. Philadelphia is roughly 300 miles from Pittsburgh. Travelling only 100 miles westward from Philadelphia would barely get them past Hershey. (00:17:53)
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.