I second the 2nd row... IMO...not keen on putting a seat in a seat that can come out that easily... I bet Toy prolly tested it.. but ya never know... I cringe when I see kids in cars seats in a wrangler as well...
I agree that the second/middle row is probably the safest location for car seats and that is where I have my car seats. I have used the third row for the child seats a few times when the 80 was pulling minivan duty moving visiting friends and relatives with young children around.
The middle row seating in the 80 is a 50/50 split. If you mount more than one car seat in the middle row, the middle row seat cannot be folded without removing the car seats. This makes difficult to access the third row seating if you have additional passengers. The third row also has very limited leg room, making it a more ideal location for car seats while adults are more comfortable seated in the middle row.
For mounting the car seats in the 80, I use the following clamp to attach the tether strap. This is a clamp that was specifically designed to mount the tether strap to the seat mount on the floor from another car.