Easy Street - S4-E12
Continuity mistake: In this episode Alan says that Eric woke him up on his 16th birthday to get his driver's license and it's a tradition for the men of their family to go with their fathers and get their license, however in season 1 when Eric does get his license, he says that Amy and Alan let him go off with Jason to get his license and there was no celebration.
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.