My advice would be to get an area for your mouth and then select those faces and extrude them inward. Then to move the mouth you could set it up with a rig if you want.

I would think that they just want the model of the building to be lower poly most likely because if you have 6 intersections on 1 flat face then you could reduce the poly count. I've never heard about ...

Yeah exactly, you could just make a normal map of things like screws in photoshop which would save you some time and keep your poly count down.

Hi, I'm not very familiar with 3Ds Max but I would UV map everything first and plan out how the UVs will look and then take a snapshot of your UVs into another program like photoshop where you can sta ...