Any option with the suffix "Effects" can be safely set to 0 without detriment to the actual FFB as they are exactly what they say, added effects brought in by popular request. They mostly just add in vibrations and bumps that one would feel all around and not necessarily on the steering column. They're not so much canned or scripted as they do have correspondence with what is going on in the physics engine, it's just that they normally wouldn't be forces transferred via the steering column to your wheel.
The 3 main options you should concern yourselves that correspond to the actual FFB are Gain, Filter and Damping. Filter is used to reduce clipping, it culls off spikes and damping as expected applies an envelope to the FFB making it more "mellow".