Concerning your question about Gatsby and Wilson in The Great Gatsby, the enotes Study Guide on the novel says this about Wilson:
George Wilson feels henpecked by his wife Myrtle. A victim of circumstance, he has a poor life and can only work to make a living and must ask the man who is having an affair with his wife, Tom Buchanan, for a car with which to move away. Full of anger and frustration about his wife's disloyalty, Wilson acts on his impulses and kills someone who is just as much a victim of the Buchanans as he. According to Nick, “he was a blonde, spiritless man, anemic, and faintly handsome. When he saw us … hope sprang into his light blue eyes.” He is a true product of the wasteland between the suburban world of wealth and New York City.
Comparing and contrasting Wilson with Gatsby is a bit tricky. One can logically compare Tom with Gatsby, but comparing Wilson to Gatsby is like "bringing a knife to a gunfight," as the cliche goes. Wilson is a minor character and Gatsby is the giant of the novel. And Wilson certainly can't be cited as a foil to Gatsby: he locks Myrtle away when he suspects her of seeing someone else, and resorts to murder and suicide when she is the victim of an accident.
Wilson is cuckolded by his wife, lives in a wasteland, eeks out a living, and seems somewhat ignorant.
Gatsby is a self-made millionaire, went to university, loves purely and loyally, is intelligent, and dominates the novel.
Perhaps both men are victims of women, as well as the Buchanans, but that's pretty much where any similarities end.
Both Gatsby and Wilson have to compete with Tom for their women. The difference between them is that one is the legitimate husband of his woman, the other (Gatsby) an affair. They both want acceptance of these women and they both come from a very working class background. Wilson works for an honest living trying to stretch every dollar. Gatsby likely works illegally and throws money to the wind regularly.
The duration of Nick's time with Gatsby and therefore our time as readers might make Gatsby seem like the character Nick holds greater sympathy for. However, by the end Nick is growing disgust for Gatsby's obsession with Daisy especially when it tosses morality out the window. Nick gives little report on Wilson, in fact he seems to always report directly what's going on with Wilson with little emotion.
Regarding Gatsby, Nick "had enough of all of them [referring to Gatsby, Daisy, Tom and Jordan]" and he thought Gatsby "despicable." This is all just after the accident.
By the end of the whole story though, Nick's sympathy toward Gatsby improved. He felt terrible that no one paid honor to this man or cared that he was dead, which maybe rightly indeed honored his life. Was it a life of significance? Maybe only to those who showed up for the funeral thought so. This earned Nick's renewed sympathy and he continued pursuit of arranging a respectful ceremony, if that was possible.
Wilson and Gatsby are similar in that they both wanted the American Dream. Both men are working hard to achieve this dream of a better life. They both want this because of women. Gatsby wants to get Daisy and Wilson wants to keep Myrtle. They think the love of these women will make them happy. They are different in that Gatsby has money and that is the first step in getting his dream and Wilson is not even close to achieving his dream. Another difference is that Gatsby took his future in his own hands to make his dreams come true. Wilson is still whiting on another person (Tom) to help him achieve his dream. Nick is more sympathetic to Gatsby, just for the fact that he knows his situation better and he is attached to him emotionally than Wilson