I believe in the last few lectures there has been a few mentions on Unity’s lack of support for nested prefabs.
I just wanted to share that in today’s Unity Keynote event in Berlin they announced a new prefab editor mode and support for nested prefabs. Already available in preview and fully available in 2018.2 this summer.
If there is a revision to this course for 2018 I would love to see how that changes some of the lectures and mechanism that we’ve put in place due to this current limitation.