Just joined, but I'm very interested in the towing aspect of this vehicle.
fyi, you are both partially right:
There are 2 ways to work the numbers when you need to know your ACTUAL towing capacity.
1. The best way is to always start with your GCVWR (combined rating). Not sure what that is without the tow package, but I believe it's 9700 lbs with the package on the Outlook. You then subtract all of your known weights. I think an empty Outlook is 4700 lbs, leaving 5000 lbs for the loaded trailer and whatever you put in the vehicle. No adjustment needed for the driver since you are looking at actual weights, not an abstract rating. If you know exactly what your loaded trailer weighs, subtract that from 5000, and what left is your capacity for people and stuff in the truck. If you haven't bought the trailer yet, then subtract the weight of your family and your estimate for vehicle cargo from 5000, leaving you with your actual towing capacity. Note that whatever these calcs leave remaining, the trailer can never exceed the MAX tow rating (4500 lbs).
2. For vehicles that don't list a GCVWR, you have to do it the stupid way. Assume you can tow the MAX tow raring (4500 lbs), with nothing else in the vehicle but standard fluids (gasoline, etc) and the driver. Then, for every pound of people, pets, or cargo you put in the truck, you must subtract an equal amount from the MAX tow rating to get your actual tow rating.
What I don't like about this is that it limits you. In option 1 above, you can see that you can actually tow a 4500 lbs trailer with 500 lbs of "whatever" in the truck. Yet method 2 only allows the driver (150 lbs, 200 lbs, whatever). I much prefer to use actual weights subtracted from the GCVWR.