First of all your I don't know think you know this but there are other kinds of magical beings, they all fall under the term "Magical Society". It includes spirits, were-wolves, fey-creatures, half-breeds, etc. Magical Society is organized into several well connected city-states. In general these cities are in places that would normally be considered inhospitable or to not exist, places like deserts, deep-ocean, high in the Himalaya's. Each city runs its self by it's own rules, some are archaic, king council type of things, some are more modern, city council, mayor, yada yada. They all answer to the Arc Mage council, a small group made up of the oldest and most powerful mages, they decide things that effect all of magical society. They're also the ones who deal with the conventional leaders, I would be suprised if Patriot Punch! hasn't ever dealt with them.
In terms of class it really depends on the city, but most are like your average capitalism, with upper, middle, and lower, decided by family income. There is however a greater amount of attention payed to family in terms of status. My family the Stitch's are incredibely well respected due to my fore-fathers work.
Oh by the way who were you talking to I heard voices? Well now your getting into to stuff I don't really know about. I've got no idea where the governments orginated from, or how they keep most people in government from knowing about it.
As for wars, well there have never been any in between the city states, but magical creatures have fought on both sides in other wars, my father for instance fought in WWII with his homeland Great-Britain. Besides that disputes between them are very rare, and are always solved by the Arch Mages fairly quickly.
We trade just like everyone else does, trains, planes, and boats. They way I understand it is that governments have certain ports where they have custom officials who already know about magic and do the inspections. Actually you would be very suprised how "normal" most magical creatures look or can look. Richard have you ever heard of something called a "weirdness filter"? Well we live in a world were myths are busted, mystics are debunked, and all sorts of supernatural things are given rational answers. As a result most people have developed a resistance to believeing that magic exists, even when they are shown it, they say things like "Smoke and mirrors, must be some rational answer, swamp gas". You've probably seen something magical long before you joined the Society and rationalized it, especially because you an engineer, my dad says engineers or prone to rationalizing everything. The fact is it's just not in human nature to believe magic exists. Trying to force otherwise causes tensions. This willingness to believe magic doesn't exist is what we call a "weirdness filter", how people disregard things that are too weird for them. It allows people like me to get away with a lot, especially when you consider that flying, making ice, manipulating plants, casting illusions, causing earthquakes, creating armor from no-where, are all powers our teamates have without the use of magic, supernatural stuff just doesn't stand out as much as some would think.