So you are looking at 400lbs total. The Broncos tow rating is 3500LBS so that is about 350lbs at the tongue. I would think the 400lbs would cause the front end to lift quite a bit and rear to sag this will negatively affect your brakes, steering, and lighting. The soft suspension is good for off road but lacks in towing. I imagine you can beef up the rear suspension to accommodate the scooter but I have not seen any aftermarket parts for that yet. But I suspect they will be coming.
Also you are only 50lbs over so that might still be in the safety margins.
Bronco Nation 1100. Everglades, Desert Sand
Res: 7/30/20 ordered 1/22/21 reorder 10/15/21 changed to Everglades 3/9/22 schedule 8/29/22 bumped to 9/5; 9/7/22 blend, 9/9 Mods, 9/26/22 completed, 10/7 shipped, 11/3/22 delivery