What do you make of Skinner's comments about free will?
Skinner identifies free will as a fiction because behavior is the result of the environment. When environment is controlled on its contingencies of reinforcement then the behavior can be trained and changed properly to achieve an specific task.
https://newlearningonline.com/new-learning/chapter-6/supporting-material/skinners-behaviourism

Even when there's no doubt that this happens as he states, it's a simple way to analyze human behavior, since human beings take decisions based on different circumstances that are not locked on an environment but in their own history and memory. On this video about the neuroscience of free will (https://www.youtube.com/watch?v=llM1ZR1htp8) makes me think on how our decisions, that might be taken in our brain before it gets to our conscience, can go in another way once they get into our consciousness.

What is the role of the teacher in the behaviorist scheme? Nature or nurture?
In accordance to Skinner, teachers must be clever enough to identify which contingencies shoud be managed together so the behavior of learnes can get in a specific path. They are trully important as they are managers of those contingencies, and should know clearly which contingencies bring specific behaviors, and how to combine those, is key to obtain good results.

What are the dangers and uses of intelligence tests?
Intelligence tests require a good interpretation of the differences between intelligence and knowledge. Intelligence is about the potential ability to solve certain problems, and is inherited, while knowledge is the material with which the intelligence works.

About the dangers, I found pretty interesting the video of Jordan Peterson defending the viability of IQ test and how powerful they are as a tool to predict the future outcomes of people, vs. the misuse of complex concepts as race to defend certain behaviors that predict or judge the terrific discrimination between ethnic groups. https://www.youtube.com/watch?v=APneKDezEWI

REFERENCES
https://www.youtube.com/watch?v=APneKDezEWI
https://newlearningonline.com/new-learning/chapter-6/supporting-material/goddard-on-iq
https://www.youtube.com/watch?v=zXRvbkUfhIY