The reason I recommended a class III hitch is that a class II hitch, rated for 3500 lbs, is usually a three piece system. That means that there are two side pieces that attach to the frame rails of the vehicle and a center piece with the receiver box. This allows the receiver to move up and down a little, which is OK with a very light trailer, but not good with any significant weight. I have one that I tow my 1000 lb max utility trailer with.
For anything heavier, you need the one piece design of a class III hitch. One of the reasons that a class III hitch cost so much more is that it has to made to fit between the frame rails exactly, it is not an adjustable fit like the class II hitches. So, while 5000 pound rated capacity may seem like overkill, you need the solid, one piece design.
BTW, when I say frame rails, I mean to include the formed frame rails that are used in the unibody type vehicles such as the Caravan as well.
I stand by my advice. Unless you have a significant electrical load in eh trailer, you don’t need the larger alternator or battery. Ceramic brake pads will help handle the additional heat from stopping the additional weight. You could add slotted rotors if you want, but not drilled rotors. Slotted rotors will decrease the brake pad life though.