Campaign Update rules are primarily used to Update the Campaign Properties Automatically and can also be used to send a Notification every time a Custom field related to a Campaign is updated.

Yes, you can set them by adding ‘Set Naming Convention’ action in Rule Builder.

Only draft messages.

Draft rules are applied on the outbound message while the content is being created whereas Draft Update rules are supposed to be deployed on an already drafted message to change certain aspects as and when required by the user.