There is a HUGE difference. "2011-2015 Jetta or Golf" includes four different platforms, two different engine families.
2011-2015 NCS Jetta sedan
2011-2014 A5 (facelifted) Jetta wagon
2011-2014 A6 Golf
2015 A7 Golf and Golf wagon
All the 2011-14 cars use the same CJAA engine
2015 NCS uses the CVCA engine
2015 Golf uses the CRUA engine
2015 engines have SCR, the others do not.
They all use the same manual 6sp gearbox, or the same DSG 6sp automatic.
You did not specify how you want to tow it. Dinghy towing will require a manual gearbox. Dolly towing you can use either.
The NCS is the cheapest and lightest. The most plentiful on the used market, too, as they sold the most. However the Golf hatchback would be the shortest, and the most "practical" for running errands, as it can swallow larger things if necessary. It is also a nicer, better built, better contented car. It also costs more, and is not as common here.
Either of the wagons would obviously be more practical, but it will of course be longer and heavier.
I *think* the A7s got some weight reduction, but much of that may have come from the return to an older type twist beam rear axle instead of the IRS setup the A5 and A6 had. This was to make room for the DEF tank.