Awesome trip for the family. All sound like good choices, I've seen many write ups with those choices especially in Africa. I think the number one concern would be parts & service in the countries you heading too. Of the choices, I think the JKU offers the best for a family of 5...... 5 secure seats with full seat belts.... and great visibility. But you'll need to travel very light. And I'd think you'll need a trailer to carry enough food and clothing and water. Even if you can pack it all INTO the vehicle you'll likely be overweight.... which will lead to breaking parts.
Look to Europe, Africa, South America. Find out what is the most common, easily serviced vehicle..... and be open to selling and buying rather than shipping one vehicle.
I imagine 4 weeks in South America, living in a rented house while finding the right vehicle. The trip should be about more than just overlanding. Join a Rotary Club, open up to the worlds biggest network. Rotary Projects overseas are incredible opportunities to meet the world.