[@FourthKing]I suppose there isn't a problem with a person owning a small gang. But remember, you'll be prompted to being recruited into a diving crew early on into the story. So maybe have a reason for that. 

:Links are capable of doing many things. The potential they have is quite vast, so I'll leave it to your creativity. If something is too powerful, I will point it out, otherwise just have fun. On a technical sense, since this is sci-fi fantasy fusion sort of deal, think of them as the magi-science equivalent of individual scrolls for 'spells' in a typical setting. But keep in mind the potency and cooldown. 'Relic' is the baseline level. Because they are relics, and inherently rare in themselves, their effects are relatively strong. More powerful, in effect, than any of the typical technology found pretty much everywhere in the Outer Ring. When dealing with such things, if one provided a shield, it would block dozens of bullets before burning out. Each incremental level is a noticeable increase in power. Relics have 3 levels. And as a comparison, there is a magnitude of difference between the end level of 'Relic-III' to the power of even the weakest 'Artifacts'.  

No one has those, for obvious reasons. 

Catalysts are a synthesized arcane-based energy source that has been hard condensed in a crystal and housed within a protected core. Usually some sort of alloy. They are mainly used in larger machinery, starting from B-Class and up, ending at D-Class. The process and design is incredibly complicated, so they are usually bought from manufacturers. Certain talented people might be able to make their own. Because of their immense power output, and dangerous fallout state, any B-Class and up are prohibited from public use and handling. And by 'public', we're talking about big companies and corporations, who can actually afford such things. Even an A-Class, which is [i]greatly[/i] insignificant when compared to the next class up, can power an entire house around the clock for a month. 

Most catalyst-power guns shouldn't need anything more than an A-Class to function. Of course, such powerful technology(talking about the gun itself) is reserved only for Magistrates, so having something like that would be illegal. Not that any of your characters would care. 

And for the final question, the majority of the population eats something along those lines, yes. There are synthesized foods that actually taste somewhat good. But those are expensive luxuries.