Being frank, you've painted yourself into a corner. With that many growing children some things are self evident; they are going to grow, both in needs and size/weight; that many folks require a very large vehicle just for them to fit; trying to tow a trailer of any size with that many people and a vehicle sized to fit them (and the gear/toys they will want) is almost impractical unless you want to shell out 3-400k minimum; an "it might/I'll make it work" approach is impractical and dangerous for you, your wife and kids and everyone else on the road; losing money on the trailer should be of little consequence compared to the welfare of the family.
Those things said, you still haven't spoken of any specific vehicle payload. I am assuming because these are all hypothetical. As has been mentioned you cannot go from any brochure, ad, salesman, you tube video etc. when trying to fit a tow vehicle to a trailer; the trailer, and in your case, the large load in the vehicle will dictate what vehicle that is. Smaller trailer = less requirements. Class A for that many folks? I don't know but the one I almost bought for DW and myself was north of 400k. 6 people with 4 being small kids I'd want at least a 70' bus with 10 slides. The one we looked at was I believe 42' and seemed kind of small for just us 2.
You've also not expounded on the need/requirement for 4 wheel drive? Why do you need it particularly? It takes away a considerable amount of payload if you don't need it and the Quigley conversion is pretty costly. Depending on what kind of "conversion" it can really affect towing/drivability.
You've got some choices to make. You have the kids (if not more) and you bought the trailer. Now it will be a tow vehicle that can pull that trailer and fit the family. Don't kid yourself thinking you're going to travel "light", no water, 1 bicycle so the kids can share kind of stuff to save weight - it ain't gonna happen. Get a big enough truck to grow with the family, take a chase vehicle or try that 70' RV I mentioned...
And yes, George is a good guy.