Not thinking of anything for pause - the super control is either driving the sub to the min value or max value, don't see a way to interrupt that drive.
One other weird thing - in the first cycle in the layout above, a single press of Start / Stop will stop. After the first cycle, it takes a double press.
Re: triggering one button for on and one for off - you should be able to gang together a sequence that operate two buttons, one inverted, send ON only, on ON is for the Start, other ON is for the Stop.