Just a little info about LSAS and WAGS. They are two separate animals.

LSAS works when the autopilot is off and you have less than 2 pounds of pressure on the yoke. It uses 5 degrees of elevator authority to command or hold pitch changes when there is no input from the pilot.
You do get positive nose lowering when the spoilers deploy on landing. That assumes that you are not holding the nose off the ground with positive back pressure during actual touchdown. That's why when we land you are suppose to release back pressure at 10 ft. to essentially a neutral stick. You can always override LSAS.
With regards to stall protection it will use it's 5 degrees of elevator authority to lower the nose to get away from the Pitch Limit Indicator (indicator of Vss/Vso). It will not, however, dump the nose to do this. Demos I've done in the sim show this to be a very slow process. I do not believe the nose down pitch you see on the video was caused by LSAS.
WAGS tells you when you are in windshear and provides you guidance on how to get out of it. If the autopilot is on (LSAS not working) it will follow the guidance, if the autopilot is off you have to follow the guidance, ie follow the Flight Director (again more than 2lbs of pressure on the yoke, LSAS not working). That simple.
Hope this helps.
Disco