The ball coupler should be 2 inch, unless it has been changed in the course of its life.
The trailer brakes are 12 volt
electromagnetic. The braking force varies according to the amount of voltage applied, from 0-12 volts. A brake controller needs to be mounted in the tow vehicle to activate them. The most basic type currently available is a pedulum type, which applies more or less voltage to the brakes depending on what angle the pendulum is. It will only apply power to the brakes when the brake pedal is depressed, so the brakes will not activate when simply going downhill.
The high-voltage components are 120 volt, 60 cycle. The easiest way to deal with this is to get a converter to go from euro standard 240 down to 120, otherwise you will have to replace every item that is 120. This would include, but not be limited to, the air conditioner, Univolt (battery charger/power supply), fridge, and any other appliances and lights that are not 12 volt
Also, be aware the trailer will have a tongue weight of 400-600 pounds, depending on what is in the trailer. Most euro models have a tongue weight of around 100 pounds or so.