The Rav4 outright prohibits 3 humans in the back seat at any given time. It is a 4 seater vehicle with 5 possible seating positions.
With the Sorento and Santa Fe, neither outright prohibit 3 across or side by side with adults or car seats, but the car seat manufacturers DO prohibt the install of car seats or booster use when there are overlapping seat belts or lowe anchor straps. 2 car seats or boosters outboard with a non-boostered pre-teen/teen/adult is still not kosher as there would still be overlap.
With the Sorento and Santa Fe, neither outright prohibit 3 across or side by side with adults or car seats, but the car seat manufacturers DO prohibt the install of car seats or booster use when there are overlapping seat belts or lowe anchor straps. 2 car seats or boosters outboard with a non-boostered pre-teen/teen/adult is still not kosher as there would still be overlap.