I'm now completely confused about tow vehicles

I also think buying a 250/2500 crew cab (or at least extended cab for the dogs) truck would be the way to go. Finding a good quality truck to fit your needs would depend on your budget. Ideally find a fairly new certified one still under warranty from a new car dealer. A gasser would be fine for that trailer since it appears frequent towing is not in your plans.

You could even get by with a newer 150/1500 with the right towing package, engine, rear axle.