A small lighting challenge

I thought I'd share a challenge that I'm giving my Animation I students in class tomorrow. Inspired by a similar exercise I was given back at Pixar University, the task here is to take the starting scene file and light the scene to match the target image. No shader changes allowed!

The target image isn't anything fancy, but matching it does require one to be comfortable with some very important basics of digital lighting. I'm thinking in particular of three-point light setup, using light linking (or whatever your software calls it) to direct lights to shine on only certain objects, creating soft shadows, making lights cast specular independently of diffuse light, and a few other things I'll keep quiet until the exercise is over.

The starting image (i.e., if you poke render after opening the scene file):



The target image:



The starting scene file can be found on my course website.

Please try it yourself if you're curious. Post your results and discoveries, too.