Menelaus most strongly affects the epic plot through his

Menelaus most strongly affects the epic plot through his compelling speech. As soon as he started giving his speech, everybody stopped talking in order to listen to what he had to say. His speech touched everybody's heart and they decided to follow his advice.

well stockyards mean a large yard containing pens and sheds, typically adjacent to a slaughterhouse, in which livestock is kept and sorted. and i'm assuming that by party you   mean a large group of people which does make sense because chicago is a very crowded place much like new york. stockyards tend to take up a lot of room due to needing the area for pens to keep animals in and the fact that stockyards are usually right by slaughterhouse where they process and distribute the product. so its much like a zoo but with some dead animal products close by.