I doubt a single shoulder fired “stinger” missile would be able to take down AF1.
True, since they are infrared seekers.
Also AF-1 (the 747s) are equipped with flares and missile plume sensors; meaning that while the ride for the passengers would suddenly be ‘robust’, it’s unlikely AF-1 would be brought down by ‘stingers’ — even when low and slow for approach at Andrews. I feel certain the crew has drilled for this potential event.
Depends upon where the missile impacted.
That depends on altitude and aspect of attack. Also consider a barrage.