First of all; don't use notepad to edit the files, it can mess the file up (at least it did for me). I prefer notepad++, crimson editor also works well.

Now, what you need are some tutorials.
Adding a new unit Skip to step five. Also EB uses it's own hidden recource system, look here for an explanation on that.

Here is a tutorial concerning the traits & ancilliaries. The simpelest way to remove a trait is by removing their triggers; the character you start the game with may still have the trait, but the next generation won't get them.