One of Sidney's defenses of poetry is that it inspires action. That was also one of the criticisms of it by Northbrooke - that it inspires people to sin. Same rules apply, except that I've focused the questions a bit. Trissino talks about the differences between how comedy and tragedy teach. They are pretty distinct.
Same rules apply.
St. Augustine notes that the Romans didn't allow playwrights to make fun of living persons. We allow that, within reason. Note that, despite all his dislike of theatre, he uses it to argue against the Greek and Roman gods. So it seems quite convenient for him. Again, use these questions as a guide.