Well I'll try to answer some of the questions.
The volumetric light shafts, I'm guessing were done with LYTEFX, a long lost decal set, pretty hard to find as most links are dead.
The doors are simply HUD images, they are triggered by the scripts for the doors. The stock images can be found at
FPS Creator/files/languagebank/english/gamecore/text.
The animated desk is an animated model, it is triggered by a script ,much in the same way an opening door is.
The lighting of the fire was scripted, activating a decal. Not sure about the light maybe activating a shader by script, maybe just a light..
The character at the end looked to be custom, you can make characters follow waypoints.
If you are a beginner, be sure to read the FPS Creator manual, and the ocfpscguide, in your Docs folder.