These are colossal Roman figures, who cannot be reduced to a few hundred words. So, let me make some broad generalizations.
Caesar and the Gracchi were alike in that they both were champions of the people. The Gracchi wanted to limit the acreage of the aristocracy and redistribute this land to those who had little—such as veterans. In the end, their plan was thwarted as both were killed by the senate. Caesar did not pass a land reform, but he was seen as a champion of the people. This is the vital connection between Caesar and the Gracchi.
Marius and Caesar were also alike in that they went against the senate. In fact, Sulla stated that there were many Mariuses in Caesar. Sulla's words would come true, as Caesar marched on Rome and became dictator for life. It should also be mentioned that Caesar was Marius' nephew.
As for Sulla and Pompey, they were the opposite of Caesar. These men sided with the senate and fought Caesar—the latter more directly. Sulla gave the power back to the senate and even enlarged it. Pompey was the champion of the senate and fought with Caesar in a civil war.