Audio problem: When Janet is talking to Michael about how she loves Jason, there is a shot looking at Michael with Janet to the right. Janet is talking but her lips aren't moving.
Audio problem: While Accountant Steve Merchant is getting angry at Michael his words do not match his jaw motions during the shot from behind Merchant's face wherein he says "Now if you'll excuse me". (00:17:10)
Answer: No, he is fictional. The joke is that, despite being handsome and charming, Larry Hemsworth is so overshadowed by his brothers that nobody else has heard of him and he feels like a failure.