Answer:
No, No
Step-by-step explanation:
In the simplest of terms, it would be unwise to measure each of these things in meters, because they're not the closest unit for measuring such a thing. However, an argument can be made for each case.
For the pencil, although one meter is much bigger then the length of a pencil, your problem may be in terms of meters, and it is easier to measure the pencil in meters than to change the rest of the problem into a measure more suited.
For the hallway, we have the reasons given previously, along with the fact that we can be much more specific in millimeters. So if a problem required specificity, then we could use millimeters.