WDH? No, it likely isn't a must BUT it will make difference, especially one with built in sway control. I was uncertain about getting one for my 16BHS it made a big difference towing it home 150 miles. My vehicle is rated for 5225# towing. Trailer weight was 3100#. Bought the WDH used from the dealer and they set it up for me.
If you don't have an electric brake controller, you need to add one. If your vehicle has the tow package, some include the controller, some just a plug in pigtail for one.
If going with two generators, get the synchronizing kit so you can run them together.
Tires? Most will say upgrade. The newer Goodyear Endurance trailer tires come highly recommended. Please search TIRES here and get a pot of coffee going