No, because unlike a true guild in the medieval sense they will have no secrets to keep, and be closer to the local chiefs of the district. If anything, I would expect the leaders to be trying to increase their trade's population since that directly increases their power. Again, think union bosses, not guild leaders. And assuming that the options work like they did before, the change will only affect the City, not our entire polity.
No, the point of a guild is to teach a complex skill in a society where things like reading aren't all that common. They became issues over time, but especially in the time after the fall of Rome, they were the only reason certain specialized knowledge survived.
Glaze: Another society
Wheel: Invented before our society began, improved by the Nomads
Compound bows: No idea
Metal: Yup. A priest. Very good!
Salt: Priest.
Disease cure: Priest.