Your best source of informaion on that subject would be the Jeep dealer.
Not neccessarily. Two dealers told me that the new Libertys, infact anything post manual trasfer case, were not towable four down, yet if I recall, there are peopl ehere who are doing it. The best source of info is the vehicle manual. If it;s towable, the procedure will be in the manual. My Grand Cherokee manual has a page on towing four down.
Brakes depend on weight. Most states require brakes over 3000lbs. If the jeep is less than that, no brakes required.