Sixteen Candles and Four-Hundred-Pound Men - S4-E9
Factual error: The match between Vader and Jake the Snake is supposed to be taking place in Philadelphia, presumably the Spectrum, but the establishing shot of the building is actually the Great Western Forum in Inglewood, California.
Factual error: In this episode, Eric and Cory stop in Pottstown, Pennsylvania on their way back to Philadelphia. Cory protests, reasoning that stopping there is pointless because they are only three hours from home. Pottstown is roughly 40 miles from Philadelphia. It certainly wouldn't take three hours to get to one location from the other under normal driving conditions.
Shallow Boy - S4-E5
Factual error: After Eric offends Corinna, she is able to write, record, mix, package and distribute an album of music within, at most, a matter of days to spite him. Accomplishing all that within such a short amount of time would be logistically impossible.
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.