No, they're all very unnatural. Generally, I only use "to get to know" when I am talking about gradually becoming familiar/friendly with another person.
"There is a new girl at work. I'm looking forward to getting to know her."
"I enjoyed getting to know you. It's a shame you're leaving the country."
"There are so many new people in my class, I haven't got time to get to know them all."
For your examples, I would use:
1) Did you find out the coursework deadline?
2) When I was at school, I found out you were sick.
3) I don't know how he found out that I'm studying at XXX school.
Student or Learner