1. Yes, an event is received by the person being unassigned.
2. You can have Passengers - x, where "passengers" refers to the stat by that name found for each ship on the rules page, and where x = PCs already on board (1, if it's just the pilot). Yes, multiple NPCs can be located in the same room, provided the ship has sufficient passenger capacity.
Ok, so if I understand this correctly, if the max passengers is 1, then only the pilot can be seated in the ship, and if the max passengers is say 6 then you can have the pilot and any number of NPCs/Droids under the weight limit for that ship?