[@Orixi]Hey, thanks for your interest! To answer your questions:

There's definitely a black market that's thriving just underneath the service. Ranging from the sell of illegal wares to those who simply wish to work outside of the influence of the guilds, there's plenty of business done under the table. There's no set location, exactly. Multiple black market rings can be found in the poorer districts of the city, and several markets have 'known' merchants who circumvent the guild rules and sell items that they shouldn't. So those would be the closest places to actual hubs for that sort of thing.

It depends. Dall's official guards aren't too concerned with fraud, but most of the big guilds have their own private mercenaries that handle illegal dealers. Leg-breakers and other hired goons will either 'disappear' people working around the law, or intimidate them into joining their guild. Official penalties can range from simple fines to jail time, depending on what's being sold. A piece of pottery, for example, might land you a minor fine. But if you're dealing in something like artifacts? They're going to lock you up tight for a good while. Slavery is a fairly typical punishment for that sort of thing. The crown has prisoners 'work' until their 'debt' is paid.

The skeletal remains of skyscrapers are still around in a lot of cities, yup! But it does depend on a number of factors. A few cities like New York suffered a lot more structural damage than others like, say, Kansas City. In general, though, most city ruins are more grown over and abandoned than outright rubble.

Oh no, I'll be giving specific city/state names to let ya'll know where exactly we're at. So you definitely don't have to worry about getting lost.