No offense, but 5 yr olds need to be buckled into the seat with the car's seat belt or in a carseat/booster seat. You buckle and unbuckle them, those are the rules, captain's chairs or not. If they get out of their seats, you pull over and stop the car until they get back in and buckle up. Or you turn around and go back home. That they don't get to go anywhere until they learn that don't get up and out while the car is moving.
And no, a bench seat is not a bad thing. You learn to adapt. Many of the bench seats have a pull down that divides the seat into two seats. The biggest problem you might have, depending on how large your family is, is the kids wanting to have their own space, they go through stages of "he/she's touching me" and don't want to sit close to a sibling.
Happy car shopping!!!