The answer to most of these questions is yes, but you need to change your style to do what you want. The way it is set up right now, the pot simply sets the variance, same as “color change”. If the styles used don’t take any action based on the variance, then ProffieOS will use a rotating color wheel to adjust the colors. However, if the styles have Variation function, then it’s simply up to the style to decide what to do.
(4) is not something you would do in the style code though, it would require a little bit of coding. (Basically just checking if the value is too high and if so, ignore it.) You could make a copy of the receiver code:
Rename it and put it in your config file, then add an if statement, something like:
class MyAnalogReceiver : public AnalogReceiver {
public:
void Set(float value) override {
if (value > 0.95) return;
SaberBase::SetVariation(value * 32767);
}
};
Then use this receiver instead of ChangeVariationAnalogReceiver.
The limits are whatever you can code. 
It sounds like you want to put something like this in your style somewhere:
Mix<Variation, Blue, LightBlue, Pulsing<Blue,Orange,800>, Pulsing<Blue,Red,800>>
You can extend the Mix<> with as many things as you want.