Just wanted to chime in with my family of 6. This was the exact consideration and ultimately we couldn't fit 6 in a truck because we also needed to fit 4 car seats and we didn't want to put a car seat in the front of a truck.
We settled on a NV3500 towing a wildwood 263bhxl, 6000 lbs dry, 7600 total allowable. The NV3500 can fit 12 people, has a payload of app. 2600 lbs, 8700 towing capacity.
This thing tows with ease. Pulls uphill, heavy duty brakes, transmission. Tows my rig with no issues.
I didn't even consider the Ford E-series given how outdated those are. Also, the NV doesn't have the cab over design which makes it much easier to work on. It's also quite modern on the inside, very quiet, and rides great even when not towing.
We took out the last row of seats, still seats 8 and there's a cavern for stuff.
