Villas,
Stall warning comes from angle of attack, not airspeed. This is why it still works with unreliable airspeed. Your V sw is really alpha SW.
The spoilers do auto retract, and the THS does stop trimming. Been on the BUS since 2003, it's always been the same. The THS trim stops and makes you have to apply pressure on the stick to maintain attitude to warn you of the low speed. If you keep pulling on the stick you then hear Stall Stall. If you Release the pressure, the attitude lowers and you accelerate. Hmmm...Think this was done on purpose? Have you ever wondered why stowing the speed brake comes so far down the stall recovery items?
I have never flown a mini bus, perhaps they behave a little differently.