Stopping and waiting for an obstacle to get out of the way

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Your desired behavior is not yet available out-of-the-box. However, you can configure the local planner to follow the global plan by activating and configuring via-points.

Then, you could add a separate small node between the twist message from the local planner and the robot, which slows down the robot in case of any potential collision (e.g. by considering the maximum deceleration). The additional issue here is, that you would need to also subscribe to the cost map or you need to process your sensor data manually to get the obstacle positions. In case the local planner still tries to avoid the obstacles, you might reduce the parameter weight_obstacle of the local planner to zero.

Another possibility is to add such a stopping behavior to the local planner, which should be straight forward (before actually sending the velocity commands). I would be happy to accept any pull request ;-)

Doing it via the global planner (actually the move_base goal) looks more easy to me.

Let's say we have a target and a global plan to get there. The local planner is trying to follow that path and generates motions if the global path is ok. Then suddenly, an obstacle appears and the robot's footprint cannot move on the previously created global path. Now, the global planners usually (AFAIK; commonly) create another path to follow. This is called self driving approach.

At this point which you seen an obstacle on the path, instead of following a new global plan(you can understand from its topic when a new one arrives), you can just cancel the navigation goal. After the costmap is clear (the obstacle moved away). Send the target goal back again and it will generate a good global path like the part which was remaining previously.