1) you would need to add the filed to the content table to hold the notes, add a new form element to the content_insert and content_update pages, then update the insert and update record behaviors on content_insert and content_update pages and bind the new database columns to the new form element.
2 - 3) you can edit the width and height of the editor instances by editing the following code on the content _insert and content_update pages:
$CKEditor_config["width"] = "98%";
$CKEditor_config["height"] = "300px";
Power CMS Does not support live page editing that you are asking about though. This is not supported in Power CMS