When you create a class with ezobjectrelationlist datatype, you have to select the type. If the type is New objects. You go to content, create an object of that class and New objects. So when you are creating the object, you create the new relation objects, and you edit all the objects that are from that relation in the same template. If you reedit this object, you can edit all related object at once.
Tell me if is not clear please, i know my english is not good :-(
Yes, I think I know where you're going. But I'm not sure that would be easy/possible without severe changes to the kernel functionalities (edit view and related) or writing your custom edit view-set. Or creating a complex datatype overriding objectrelationlist datatype, that would actually provide interface for object editing.
Anyway, no experience with that particular problem here, sorry.