I believe you're overcomplicating this a little
Just open the CharacterCreation map in the editor, it'll load all the .lsb files you're editing by hand currently, and place the characters and triggers that the game needs, save the changes and it'll save the diff in your mod.
The MapKey-s are the object ID-s (GUIDs) used by the game; the only requirement is that they should be globally unique (duh). If you REALLY want to do this the hard way, then use this to generate some:
http://www.guidgenerator.com/
