About door glitch:
It's an animation, if you hear the sound it's the door opening and you get teleported on the other side. Couldn't animate it that much because it would have been tedious as most lights are baked (static). So when you no clip in them your character continues flying and then controls are resume. It should be patched (when noclip = ON, then disable these door animations).
For the gates, if you run into them they open, they have weight, could you confirm it doesn't work ?
For FPS issues, it should be the oposite lol, that's very very strange. I'm investigating.
And not sure to understand the last part with the ToT ?