Unity - NPC - Little project!!

Note: I have this project solution in old version (8 months ago) - the only thing we need is to make the apartment 2-floor instead one floor, and in newer version! The NPC logic is already done Build two floor house with rooms and passageways, place furniture in it and add a number of NPCs (at least 3) that move from place to place (as in a SIMS game) in a certain order. The order can be random, ascending or descending. The characters should be humanoid with animated walking. Add doors in the passageways that open when the NPC approaches them. In order for us to track the NPC we can make the walls transparent by a certain percentage.