Do you know yet if there's a comparable mod that works for the original tdd? I heard that rebirth has a comparative safe mode (adventure mode iirc?), but I don't want to have to buy a whole 'nother version of the same game just to get that.

I assume you mean disabling the monsters? You can do this yourself very easily.

In case you still have an interest in this, or for anyone else looking for a "safe mode", I'll leave a guide here:

1. - Go to SteamLibrary\steamapps\common\Amnesia The Dark Descent\entities\enemy

2. - Rename the "enemy" folder to anything else or simply delete it.

Now monsters will no longer spawn. I would still highly recommend playing the game with them enabled, but if you want to enjoy the game as more of a walking simulator than a horror game that is your decision.

Hope this helps!