I didnt visualize them mostly because I didnt know how to.
Yes that would be possible but would require some changes, it would also have performance impact. Also what you described is already there as each particle has different size of pressure radius which is different for every combination.
Could all these established parameters be saved? What about the current state of the simulation to resume it later? In my github example all parameters can be saved via a save/load function. These parameters include these matrices which are the most important thing. I don't understand what pressure means in your simulator, nor the concept of fog.