TOW VEHICLE RECCOMENDATION

Packing around 5+ kids to wherever they need to go in an urban area in a short bus does not seem like fun.
Get a new kid carrier mini van and you can pick up an old truck or suv for towing, IMO.
Gotta have 2 vehicles anyway, right?
Minivan for mom, tahoe/suburban for dad and towing. Both will haul the kids, one will be much more convenient for the day after day kid hauling.

Nissan NV3500 is another option.

With your seating requirements, a van is the only way to go, IMHO.

GM 12 or 15 passenger van, best newest option out there. Next IMHO, MB sprinter van, 12 or 15 passenger. These are also available in 4wd. But probably very few and FAR between.
Last on list, Frod transit 15 passenger due to long rear overhang. Drive a cargo equal daily. Does not carry weight well at all. The 12 passenger is better.

Marty

APT wrote:
1-ton GM van with 6.0L/6-spd. Overkill? Sure. But easy, comfortable, inexpensive especially used, and reliable for 200k+ miles.

X2. Great vehicle for your purposes.

1-ton GM van with 6.0L/6-spd. Overkill? Sure. But easy, comfortable, inexpensive especially used, and reliable for 200k+ miles.

Since you said used I will recommend a Suburban (or Yukon XL). For that weight a common 1500 series will probably work. But, if you can find a 2500 series it would be better. I bought a 2009 2500 Suburban to pull my 6,500 pound boat and it does a nice job, even with up to 9 people inside the vehicle. If you get a 2009 or newer the six speed automatic will automatically downshift when braking or to hold he cruise control speed. Earlier models didn't do that.
They stopped making these in 2013 so that's the newest you will find.

To me, daily driver and around town doesn't scream 12 passenger van. I know some folks who do it, but it's because they can't quit having kids...they're up to 8 or 10 or something now!!
Oldest one is out of the house and the youngest 2 are 1 in diapers and one still in the oven!
His "other" car is a mini cooper because he hates driving the "bus" in the city. Same reason my wife went on protest with her favorite Dodge Mega Cab when we moved to the Seattle area. 20'+ long vehicles are great until you're in the Safeway parking lot and half the spaces are marked "compact" and the rest seem like they ought to be after you shoehorn a big rig into one!
3 row SUVs are not convenient if the 3rd row has to be used frequently either. Never had one until recently and the few times it's been a people hauler for 6+, back seat get flipped up, seat back flipped down, back the other way to get out of the vehicle.
Honestly a minivan is the best around town kid hauler for 6-8 persons. Not much of a tow rig though.

Depends what your budget and “6 or more” actually equals. Is it $10k and 12 people or $40k and 7 people?
The 2 recent posts are steering you towards basically new or almost new vehicles.

Towing capacity AND room for 6 plus is full size van or suv.
Just pick your budget and start there.
$5-6k can get you a nice older 4wd suv with 3 rows and big V8 towing power and about 100k miles.
$50-60k can get you more towing power with the same capacity.
Van can get you more capacity but less luxuries unless you’re spending close to what a comparable suv costs.
There’s dozens of options but you have to narrow down budget, wants, needs and seating.

I like the Ecoboost Transit because I like more power, but if you are not so concerned about power or speed, then the GM Express 2500 can be optioned with a 2.8L diesel. Max towing is 6,700 with that engine.