If by CMS you mean a Custom Management System, separate from the editor, then no, not really.
You seem to be talking about 2 very distinct things, images and words.
If you want the enemy or player to say something, then you have to put it into the appropriate event. There is no alternative. There are scripts which enable you to type out your dialogues in an external file, but then you have to code and insert each little bit of dialogue into a particular event, so that approach is far more time consuming than typing it direct.
You speak about editing every item to do this. You are not editing anything when you are doing your dialogue, you are creating an event from scratch. Events do far more than just dialogue, they are the very backbone and legs of your game.
There are lots of ways of customising your menus. Some can be done with events; most will use scripts in some form or other.
There are many, many resources (a lot of them free) which you can use to customise your images - I assume by that you mean your sprites and tiles - if you don't want to do your own art work.
