[Vuejs]-Self contained component data model vs master root data model

It all depends on what your child-components are responsible for. If a child is extending the functionality of your parent component then the state should always be maintained in your parent component. For example in a CRUD based situation instead of creating separate components for create and update you can write only one and maintain its state (updated/created) in your parent component.

If in your current-order you are not updating anything related to the order then no need to maintain its state in your order i.e. if meta-data can be treated as a separate entity of your order no need to maintain it in the parent. But in case both order and its meta is one single entity, you should maintain its state in your parent.