These parents need to decide if their on-going connection will be a respectful and dignified one, or if it will it be ugly. If they choose ugly, their children will experience a great deal of stress. The children will likely invest significant time and energy to try to prevent and to try to repair their parents' quarrels. That means the children will have less time and energy to devote to learning all the things they need to learn to grow up to be self-sufficient, responsible adults. Also if the parents choose to interact in disrespectful ways, they will teach their children to treat others including themselves, with disrespect.
Children learn from what they see their parents do.
If divorced parents really want to meet their children's best interests, they need to develop new ways to deal with one another to make the many decisions that will need to be made. One way to do this is for the parents to meet regularly and frequently. The meetings should be at a neutral place. The meetings should be held even if there are no problems to resolve. In fact, it is especially important for divorced parents to meet when there are no problems so they can experience interacting with one another under relatively pleasant circumstances.