Questions

[Romulator]

I don't know if there's necessarily a way to "overhaul" it, but I believe in game.cfg, there is a drainage float. You can lower the amount, or even make the value null so that the lantern lasts forever.

Most errors with monsters are fixed by opening them and saving them in the Model Editor. I do not understand how you can run the Level Editor but not the Model Editor...

In terms of your maps not updating, delete any map_cache files wherever your maps are stored. That should update them. If not, then you need to run your Level Editor as an Administrator each time, or edit the permissions on your redist (retail) or Amnesia - The Dark Descent (steam) folder.

The errors at the bottom suggest you have either editted or are missing some files.