Well, I have Vision Assist Package with the cameras and parking sensors but not the tow package so do I have tow assist already? You see how it's kinda confusing...add to the confusion is the fact that the dealer doesnt even know...
Most owners mention they use a Ford brake controller...mind sharing which Ford model? Again, dealer has no idea...
I use a Tekonsha Voyager brake controller. For any controller just look up the harness for a 2005 Ford F150 - I guarantee that works, because I pulled the harness and controller out of my 2005 F150 and plugged it right into my LR4.
"Tow Assist" can be enabled/installed (it's software) since you have the Vision Assist package - you can do it with the IIDTool or the dealer can do it (if they know what the hell they're doing.) You need the wiring and the hitch insert if you don't have it - easy to know if you have them, pull the cover in the center of your lower bumper cover (two 1/4-turn fasteners, use a quarter) - if there's a 7-pin round plug and 4-pin flat you have the wiring. If not, get the wiring - the AB harness mentioned earlier is spec for spec to LR, don't waste your money on OEM. The hitch attachment is big, heavy, has a big green knob on the side with an orange key - if you don't know that you have it, it's highly unlikely you have it. Check the driver's side cubby panel at the rear - there's a foam insert to hold it that can be bought, may be in there. Check every other cubby back there. It's big and heavy, about the size of a football and weighs maybe ten pounds. It ain't gonna hide, and you probably don't have one.
As far as Trailer Sway Control, everyone has that, always enabled, built into the stability control programming for all models.