ok let's help you understand how to calculate this for yourself. This may help clear up some confusion. This way a salesman won't sell you something you really can't tow.
You need to know more about your trucks capabilities than just my truck can tow x lbs. (I learned this the hard way). Most TV are limited by their payload. To truly find out your TVs true towing capacities then you need to go weigh it. Load the tv up with all occupants, pets, and cargo that will be in it when towing plus a full tank of fuel and then go weigh it at a local scale (
CAT Scale ). Weigh each axle on a separate scale pad so it will give you a breakdown of front and rear axle weights individually and a total weight. Take the total weight and subtract it from your Trucks gvwr to get your available payload. Take the scaled Truck weight and subtract it from your Truck gcwr to get your adjusted towng capacity.
Next understand you will never tow an unloaded or dry trailer. Those numbers are somewhat irrelevant. You can either add the amount of weight of cargo you will tow to the dry weight (this is heavier than you think as most add 1000-1500 lb of gear) or simply use the tt gvwr to do your calculations. Being that you are just renting your first tt, using the tt gvwr is the safer route for you. Next understand that the tt loaded tongue weight needs to be subtracted from your available payload. The loaded tongue weight is typically 13-15% of the loaded tt weight. For your purposes go wiith 13-15% of the tt gvwr. Remember you will need a good wdh, preferrably one with integrated sway control like the equal-i-zer or reese dual cam (the anderson you mention should be just fine). I would think the renting dealership would supply this or rent it out? I know one of our local dealerships does.
now to take the numbers you provided above and break it down for you. I'm assuming you meant curb weight and not gvwr of 5716.
Gcwr(15100 lbs)- curb weight plus passengers (6116 lbs)= 8984 lbs adjusted towing capacity.
gvwr (7350 lbs) - curb weight plus passengers (6116 lbs)= 1234 lbs.
payload sticker (1375lbs)- passengers (400 lbs)= 975 lbs available payload.
the previous 2 calculations disagree with each other and the only way to get a real answer would be a trip to the scale, in the meantime I would go with the lower number for payload to be safe. especially since the sticker is based on the actual weight of your vehicle and not just a truck in that line.
going with a suspected 7000 lb trailer weight.... ideal tongue weight would be 13% (910 lbs) to (1050 lbs). this does not include the weight of the weight distribution hitch but it also doesn't include the weight transferred off the vehicle back onto trailer by wdh (typically a properly adjusted wdh will transfer approx 20% of tongue weight back to the trailer). I think you will be marginal and at your TV limits with this trailer. it will be a white knuckle ride. it will be up to you if you are comfortable attempting this or not. one question is it mountains or flat towing? I'm not sure i would try it in the mountains (then again I've been outmatched by a TT and had some bad experiences as a result). best of luck to you and I hope you have a great trip.