The idea is for most of the Sonic cast to be around in one way or another. The AU is set in a college town, so the cast are sort of filtered into certain sets of roles. They're either a student or professor at the university or someone living in or out of town.
To be more clear, here's a few examples:
Sonic used to be the star of the college track team but was booted due to getting into a nasty fight with his rival. Since he'd barely been scraping by academically as it was, he got flushed out of the school system and washed up as an employee of the local arcade. He's pretty broke and more than a little bitter at how things turned out, but he won't complain about being surrounded by video games and junk food all day. The day job will do for now. And, thankfully, he's got a much more competent guy in his corner to help cover rent until he figures out what to do next.
Vanilla owns a ranch just outside of town. She lives with her daughter Cream and found family Bunnie. They run a farm stand selling the extra produce that they don't use, but staying afloat is a little easier due to Bunnie's friendship with Sally. Vanilla's ranch is Sally's home away from home, the place she goes to get away from her father and pretend to live a normal life for a while. Sally also chose to attend this particular school because of its proximity to the ranch.
The college, which is recognized as an anomaly for having such a high Mobian population in the student body, is still run by humans. Two cousins with diametrically opposed views of how the institution should be run are in a never-ending power struggle. He thinks that the college should be optimized and streamlined into a business, with students neatly sorted into production chains that would eventually output productive workers on the other end. She believes in the power of the humanities and in learning for learning's sake. The point of an education is to prepare a person to interface with the broader world, and this particular community could be led to see a very, very different world on the other side depending on who gets their way.
Silver is, by all accounts, an unremarkable loser. He was sent to attend the college as part of an inclusivity program to uplift impoverished communities. But seeing as he's too fragile for sports, too scatterbrained for high intellect, and too awkward to be many peoples' friend... he doesn't know what to do with himself, and the world doesn't know what to do with him either. A malevolent being watching the town for vulnerable people to corrupt into pawns, however, knows exactly what to do with him.
